Various fixes related to monodoc/docbrowser and general dependencie fixes

Changes in general:

mono-tools is broken for mono 3, but monodoc alone buils fine and is required for monodevelop F1 help.
gnome-desktop-sharp ebuild, with useflags for all possible sub-dependencies.
Stablises mono-3.2.1(~arch)
Lots of smaller improvements.
Makes repoman happy!