Remove shortcut for 'Extend Selection to Include Previous'

This fixes a conflict with the HTML command 'Wrap Selection in Open/Close Tag' among others. Command is still present should users want to add back this or another shortcut.

Fixes #6.
Use version 1.8 of ruby for bundle items

10.7 and 10.8 only include ruby 1.8, so all bundle items have been written to work with that. Optionally supporting ruby 1.9 and 2.0 is problematic as these versions are not fully backwards compatible.

#ignore
Revert ruby 1.8