+ Robe is now to be started manually.
+ Adds more keybindings for robe (including <localleader> ' for
robe-start).
+ Use ruby-mode if ruby isn't available (e.g. editing ruby files on
remote systems), enh-ruby-mode otherwise.
+ Added rake, bundler, rvm, rbenv and minitest packages
+ Added $RBENV_ROOT/shims to exec-path. This should fix rbenv support
for the ruby version display in the modeline.