Avoid the Readline resize on mac as it makes it crashes often
Allow custom file inclusion, for your own irb functions

Closes #23
Properly load custom.rb
Keep the reloader when we are not in a console (thanks @amiorin)

Closes #25
Support for rbenv, thanks @agilecreativity !

We install our gems in $RBENV_HOME/versions/$RUBY/lib/ruby/gems/irb-config in
order to isolate the user from seeing our imported gems.

Closes #20
Closes #24
Use /usr/bin/env to invoke bash
Merge pull request #27 from funglaub/freebsd-fix

Use /usr/bin/env to invoke bash
Removed stack explorer as it crashes ruby from times to times
Fix rbenv not found warning
Extrated the logic to find our gems
Tweaking the rvm global gem path lookup

Helps in production environment
Mongoid Colors is screwing with colors

Closes #29
Merge remote-tracking branch 'upstream/master'