added history (scollback) limit of 10000 to tmux.conf
changed git status colors
Added new movement key bindings and speed up for Ruby files.

Added new key mappings for next/previous tab and next/previous buffer.
Added setting to use RVM (or rbenv) to locate current Ruby to speed up
loading of ruby files.
Merge branch 'master' of github.com:zanshin/dotfiles

* 'master' of github.com:zanshin/dotfiles:
  altered RVM prompt to include gemset name if present