[GSoC] Weekly Report #9/10 - Toolbars infrastructure via .ui files

Hello,

This is my report for last two weeks because I was on holidays 22-29
July.

Last changes:
- added image tab for Calc and Impress
- added icon as a first tab which shows file menu
- improved context changing mechanism (tab switching)

I also tried to implement showing/hiding the menubar but I didn't
finish it (has different behaviour on different desktops - Gnome 3 and
Unity).

I also have to fix the file menu because on Windows it crashes after
first click.

Regards,
Szymon