Remove various outdated infos from the README

I'll likely revamp it for 2.8.0, but for now just removing
what's totally outdated.

README.md

@@ -4,15 +4,14 @@
 
 ## Description
 
-This is a implementation of the JSON specification according to RFC 7159
-http://www.ietf.org/rfc/rfc7159.txt . Starting from version 1.0.0 on there
-will be two variants available:
+This is an implementation of the JSON specification according to RFC 7159
+http://www.ietf.org/rfc/rfc7159.txt . There is two variants available:
 
-* A pure ruby variant, that relies on the iconv and the stringscan
-  extensions, which are both part of the ruby standard library.
+* A pure ruby variant, that relies on the `strscan` extensions, which is
+  part of the ruby standard library.
 * The quite a bit faster native extension variant, which is in parts
-  implemented in C or Java and comes with its own unicode conversion
-  functions and a parser generated by the [Ragel] state machine compiler.
+  implemented in C or Java and comes with a parser generated by the [Ragel]
+  state machine compiler.
 
 Both variants of the JSON generator generate UTF-8 character sequences by
 default. If an :ascii\_only option with a true value is given, they escape all
@@ -32,45 +31,19 @@ It's recommended to use the extension variant of JSON, because it's faster than
 the pure ruby variant. If you cannot build it on your system, you can settle
 for the latter.
 
-Just type into the command line as root:
+Install the gem and add to the application's Gemfile by executing:
 
-```
-# rake install
-```
-
-The above command will build the extensions and install them on your system.
-
-```
-# rake install_pure
-```
-
-or
-
-```
-# ruby install.rb
-```
+    $ bundle add json
 
-will just install the pure ruby implementation of JSON.
+If bundler is not being used to manage dependencies, install the gem by executing:
 
-If you use Rubygems you can type
+    $ gem install json
 
-```
-# gem install json
-```
-
-instead, to install the newest JSON version.
 
 There is also a pure ruby json only variant of the gem, that can be installed
 with:
 
-```
-# gem install json_pure
-```
-
-## Compiling the extensions yourself
-
-If you want to create the `parser.c` file from its `parser.rl` file or draw nice
-graphviz images of the state machines, you need [Ragel].
+    $ gem install json_pure
 
 ## Usage
 
@@ -254,131 +227,6 @@ There are also the methods `Kernel#j` for generate, and `Kernel#jj` for
 `pretty_generate` output to the console, that work analogous to Core Ruby's `p` and
 the `pp` library's `pp` methods.
 
-The script `tools/server.rb` contains a small example if you want to test, how
-receiving a JSON object from a webrick server in your browser with the
-JavaScript prototype library http://www.prototypejs.org works.
-
-## Speed Comparisons
-
-I have created some benchmark results (see the benchmarks/data-p4-3Ghz
-subdir of the package) for the JSON-parser to estimate the speed up in the C
-extension:
-
-```
- Comparing times (call_time_mean):
-  1 ParserBenchmarkExt#parser   900 repeats:
-        553.922304770 (  real) ->   21.500x
-          0.001805307
-  2 ParserBenchmarkYAML#parser  1000 repeats:
-        224.513358139 (  real) ->    8.714x
-          0.004454078
-  3 ParserBenchmarkPure#parser  1000 repeats:
-         26.755020642 (  real) ->    1.038x
-          0.037376163
-  4 ParserBenchmarkRails#parser 1000 repeats:
-         25.763381731 (  real) ->    1.000x
-          0.038814780
-            calls/sec (  time) ->    speed  covers
-            secs/call
-```
-
-In the table above 1 is `JSON::Ext::Parser`, 2 is `YAML.load` with YAML
-compatible JSON document, 3 is is `JSON::Pure::Parser`, and 4 is
-`ActiveSupport::JSON.decode`. The ActiveSupport JSON-decoder converts the
-input first to YAML and then uses the YAML-parser, the conversion seems to
-slow it down so much that it is only as fast as the `JSON::Pure::Parser`!
-
-If you look at the benchmark data you can see that this is mostly caused by
-the frequent high outliers - the median of the Rails-parser runs is still
-overall smaller than the median of the `JSON::Pure::Parser` runs:
-
-```
- Comparing times (call_time_median):
-  1 ParserBenchmarkExt#parser   900 repeats:
-        800.592479481 (  real) ->   26.936x
-          0.001249075
-  2 ParserBenchmarkYAML#parser  1000 repeats:
-        271.002390644 (  real) ->    9.118x
-          0.003690004
-  3 ParserBenchmarkRails#parser 1000 repeats:
-         30.227910865 (  real) ->    1.017x
-          0.033082008
-  4 ParserBenchmarkPure#parser  1000 repeats:
-         29.722384421 (  real) ->    1.000x
-          0.033644676
-            calls/sec (  time) ->    speed  covers
-            secs/call
-```
-
-I have benchmarked the `JSON-Generator` as well. This generated a few more
-values, because there are different modes that also influence the achieved
-speed:
-
-```
- Comparing times (call_time_mean):
-  1 GeneratorBenchmarkExt#generator_fast    1000 repeats:
-        547.354332608 (  real) ->   15.090x
-          0.001826970
-  2 GeneratorBenchmarkExt#generator_safe    1000 repeats:
-        443.968212317 (  real) ->   12.240x
-          0.002252414
-  3 GeneratorBenchmarkExt#generator_pretty  900 repeats:
-        375.104545883 (  real) ->   10.341x
-          0.002665923
-  4 GeneratorBenchmarkPure#generator_fast   1000 repeats:
-         49.978706968 (  real) ->    1.378x
-          0.020008521
-  5 GeneratorBenchmarkRails#generator       1000 repeats:
-         38.531868759 (  real) ->    1.062x
-          0.025952543
-  6 GeneratorBenchmarkPure#generator_safe   1000 repeats:
-         36.927649925 (  real) ->    1.018x 7 (>=3859)
-          0.027079979
-  7 GeneratorBenchmarkPure#generator_pretty 1000 repeats:
-         36.272134441 (  real) ->    1.000x 6 (>=3859)
-          0.027569373
-            calls/sec (  time) ->    speed  covers
-            secs/call
-```
-
-In the table above 1-3 are `JSON::Ext::Generator` methods. 4, 6, and 7 are
-`JSON::Pure::Generator` methods and 5 is the Rails JSON generator. It is now a
-bit faster than the `generator_safe` and `generator_pretty` methods of the pure
-variant but slower than the others.
-
-To achieve the fastest JSON document output, you can use the `fast_generate`
-method. Beware, that this will disable the checking for circular Ruby data
-structures, which may cause JSON to go into an infinite loop.
-
-Here are the median comparisons for completeness' sake:
-
-```
- Comparing times (call_time_median):
-  1 GeneratorBenchmarkExt#generator_fast    1000 repeats:
-        708.258020939 (  real) ->   16.547x
-          0.001411915
-  2 GeneratorBenchmarkExt#generator_safe    1000 repeats:
-        569.105020353 (  real) ->   13.296x
-          0.001757145
-  3 GeneratorBenchmarkExt#generator_pretty  900 repeats:
-        482.825371244 (  real) ->   11.280x
-          0.002071142
-  4 GeneratorBenchmarkPure#generator_fast   1000 repeats:
-         62.717626652 (  real) ->    1.465x
-          0.015944481
-  5 GeneratorBenchmarkRails#generator       1000 repeats:
-         43.965681162 (  real) ->    1.027x
-          0.022745013
-  6 GeneratorBenchmarkPure#generator_safe   1000 repeats:
-         43.929073409 (  real) ->    1.026x 7 (>=3859)
-          0.022763968
-  7 GeneratorBenchmarkPure#generator_pretty 1000 repeats:
-         42.802514491 (  real) ->    1.000x 6 (>=3859)
-          0.023363113
-            calls/sec (  time) ->    speed  covers
-            secs/call
-```
-
 ## Development
 
 ### Release