Added flag --pod-versions to list command
Added tests for list --pod-versions
Added test for :name_and_version mode of UI.pod
Merge branch 'master' of github.com:CocoaPods/CocoaPods into command-list-added-pod-versions
Always include version in list without flag.

As requested in original PR (#1617).

Also remove some extraneous whitespace that crept in.
Merge branch 'command-list-added-pod-versions' of https://github.com/z00b/CocoaPods into z00b-command-list-added-pod-versions