Revise bundle development bundle

Made the Require Support File (sup⇥) and TextMate Variable (env⇥) snippets use pop-up menus.

Removed “Show Changes” which was for subversion.
Snippet to specify required TextMate version in commit message
Fix "Show Scope" command to include the left scope

The left-hand scope is represented by the `TM_SCOPE_LEFT` environment variable, not `TM_LEFT_SCOPE`, meaning that the left scope never actually showed up.
Point to ruby 1.8 shim

Using a shim allows us to catch when 1.8 of ruby is not present and provide other options.

#ignore
Merge branch 'master' of git://github.com/textmate/bundle-development.tmbundle into develop