RPC: added support for removing user_facility attributes

- Added missing removeAttributes() variant for user_facility attributes.
- Added and updated RPC's javadoc for some methods.
GUI: users can change category for unlocked publications

- Allow change of category on publication detail if
  publication is not locked.
Merge pull request #142 from zlamalp/pub

GUI: users can change category for unlocked publications
RPC: fix updateNameTitles method

Method updateNameTitles called wrong method from core (updateUser) so it
can change not only titles of a user. Also updateUser in core can be
executed only by perun admin.

Now updateNameTitles from RPC calls updateNameTitles from core.