Improve the documentation

README.md

@@ -1,16 +1,15 @@
 # dd-trace-go
 
-The Datadog go tracing package. Currently requires at least Go 1.7.
-
 [![CircleCI](https://circleci.com/gh/DataDog/dd-trace-go/tree/master.svg?style=svg)](https://circleci.com/gh/DataDog/dd-trace-go/tree/master)
 [![Godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/DataDog/dd-trace-go/tracer)
 
-Sample code: https://godoc.org/github.com/DataDog/dd-trace-go/tracer#pkg-examples
+The Datadog go tracing package. Currently requires at least Go 1.7.
 
+Sample code: https://godoc.org/github.com/DataDog/dd-trace-go/tracer#pkg-examples  
 List of integrations: https://godoc.org/github.com/DataDog/dd-trace-go/tracer#pkg-subdirectories
 
 ## Directory structure
 
-- [tracer](https://github.com/DataDog/dd-trace-go/tree/gabin/contributions/tracer): contains the low level API used to trace the different libraries.
+- [tracer](https://github.com/DataDog/dd-trace-go/tree/master/tracer): contains the low level API used to trace the different libraries.
 
-- [libs](https://github.com/DataDog/dd-trace-go/tree/gabin/contributions/libs): contains the different libraries supported by our APM solution. You just 
+- [libs](https://github.com/DataDog/dd-trace-go/tree/master/libs): contains the different libraries supported by our APM solution.

tracer/contrib/README.md

@@ -0,0 +1,5 @@
+# [DEPRECATED] Libraries supported for tracing
+
+This folder will be dropped on the medium-term.
+
+The new folder is [here](https://github.com/DataDog/dd-trace-go/tree/master/libs).