[GSoC] Weekly Report #12 - Toolbars infrastructure via .ui files

Hello,

This week I did:
- changed labels for some UNO commands with long text
- added possibility to add multiple Notebookbar implementations (.ui
files) which can be switched in the menubar > view.
  We can add Heiko's concept implementation now.
- added Toolbar Mode popup menu where user can activate e.g.
Notebookbar, Single Toolbar mode (on gerrit, this patch needs some
work)
- menubar hiding, but this feature is available only on some supported
platforms (don't work on gtk3) - (on gerrit, have to finish it also)
- added possibility to draw text below icon in the ToolBox, created
custom BigToolBox widget for notebookbar (for big buttons with dropdown
menu)

Regards,
Szymon