Get kernel from global kernels dir (/var/lib/qubes/vm-kernels), not per-VM. Can
be configured by qvm-prefs (kernel parameter).
New tool: qvm-set-default-kernel
For backward compatibility kernel=None means kernel in VM dir (kernels subdir).
(possibly empty) modules.img should be created in it.
Modify VM packages to:
- do not conflicts
- starts services if its VM type need it
Added core-proxyvm (firewall) and core-commonvm (common parts) packages.
