Sort `bundle outdated` output (as `bundle show`) ; add tests.
Ruby 1.8.7 does not have lookbehind ; fix the regex.
Merge pull request #1896 from richardkmichael/sort-outdated

Sort `bundle outdated` output (like `bundle show`) ; add spec.

Conflicts:
	spec/other/outdated_spec.rb
	spec/other/show_spec.rb