Select first staged item if there is no unstaged item.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Select first staged item if there is no unstaged item.
GitCommandsTest renamed to GitExtensionsTest. TranslationTest restored.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  GitCommandsTest renamed to GitExtensionsTest. TranslationTest restored.