Gnote in F12

[Matthias Clasen]

I have now changed the default panel configuration in F12 to include
gnote instead of tomboy, and changed comps to make gnote default and
tomboy optional.

This won't replace tomboy in existing installations, but new 
installations will get gnote instead of tomboy.

This also means that gnote should show up on the live cd (where we
excluded tomboy previously, due to no space for mono).

Some things are still needed for a 100% smooth experience:
- pick up existing tomboy notes (less urgent now, since we do not
replace tomboy...)
- don't show the 'start here' note initially


Matthias