Remove filename from tooltip info

Fix #125
Remove unnecessary check for empty text
Move ParameterHelper tests to own file
Increase test coverage for ParameterHelper to 100%
Add "in ..." to the tooltip so its clearer that this is about the folder
Remove trailing slash
Merge pull request #129 from owncloud/issue/125

Issue/125 Donâ€™t show tipsy path tooltip for files in root

* owncloud/issue/125:
  Remove trailing slash
  Add "in ..." to the tooltip so its clearer that this is about the folder
  Increase test coverage for ParameterHelper to 100%
  Move ParameterHelper tests to own file
  Remove unnecessary check for empty text
  Remove filename from tooltip info