Renamed category 'Document collaboration' to 'Office productivity'.
Added Evernote as proprietary.
Added ProtectedText as free.
Added icons and translations.
Renamed translation classes to match new category name (and corresponding JSON stubs).
Added english translation in all .json files.
Added JSON stubs where needed (some were missing, some ware empty like: '<p>--</p>').
Fixed some existing bugs in translations.

Note: ProtectedText.com isn't 'self-hosting' solution.
Merge pull request #712 from ptauser/master

Add ProtectedText in 'Note taking'