D29871: Enable option to show hidden folders in sidebar, plus small sidebar code fixes (eg: scrollbar display)

[Raphael Rosch]

rrosch marked 3 inline comments as done.

REPOSITORY
  R226 Konqueror

REVISION DETAIL
  https://phabricator.kde.org/D29871

To: rrosch, dfaure
Cc: kde-doc-english, gennad, fbampaloukas, skadinna