Change history and config file dirs

Now both REPL history is written to $HOME.
- Pry: $HOME/.brew_pry_history
- IRB: $HOME/.brew_irb_history

The IRB config file has also been moved to the
library directory.

Library/Homebrew/brew_irbrc

@@ -0,0 +1,9 @@
+# Note: that we use a non-standard config file name to reduce
+# name clashes with other IRB config files like `.irbrc`.
+# Note #2: This doesn't work with system Ruby for some reason.
+
+require 'irb/completion'
+
+IRB.conf[:SAVE_HISTORY] = 100
+IRB.conf[:HISTORY_FILE] = "#{Dir.home}/.brew_irb_history"
+IRB.conf[:IRB_NAME] = "brew"

Library/Homebrew/dev-cmd/irb.rb

@@ -65,13 +65,13 @@ def irb
     ohai "Interactive Homebrew Shell", "Example commands available with: `brew irb --examples`"
     if args.pry?
       Pry.config.should_load_rc = false # skip loading .pryrc
-      Pry.config.history_file = (HOMEBREW_REPOSITORY/".pry_history").to_s
+      Pry.config.history_file = "#{Dir.home}/.brew_pry_history"
       Pry.config.memory_size = 100 # max lines to save to history file
       Pry.config.prompt_name = "brew"
 
       Pry.start
     else
-      ENV["IRBRC"] = (HOMEBREW_REPOSITORY/".irb_config").to_s
+      ENV["IRBRC"] = (HOMEBREW_LIBRARY_PATH/"brew_irbrc").to_s
 
       IRB.start
     end