Return to current line with a selection (R.app & Step)

Previously only handled the case where caret was on line. Now handles the case where a selection is submitted. Both standard selections and block (option) selections. Fixes #5.
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
Merge branch 'master' of https://github.com/textmate/r.tmbundle

# By Michael Sheets (1) and statuser (1)
# Via Michael Sheets
* 'master' of https://github.com/textmate/r.tmbundle:
  Use version 1.8 of ruby for bundle items
  Return to current line with a selection (R.app & Step)

Conflicts:
	Commands/Completion….tmCommand