This is somehow related to #757, but only first (easier) step. Actual
change of QubesAdminVm base class requires somehow more changes, for
example qvm-ls needs to know how to display this type of VM (none of
template, appvm, netvm).
Make this first step change now, because starting with R2Beta3 dom0 will
be stored in qubes.xml (for new backups purposes) so this rename would
be complicated later.
HVM can set some xenstore entries (in qubes-tools/ subtree) to pass
informations about installed tools to dom0. qubes.NotifyTools service
triggers update of VM properties (like qrexec_installed).
This way, after installation of Qubes Windows Tools, the user doesn't need
to change any VM settings to use the tools.
If not marked as installed, start it in background - waiting for
possible Qubes Tools installation. If that happens, make it possible to
tell the dom0 about that fact.
Gui daemon isn't aware of multihead parameters, also gui protocol
doesn't support such information - currently by design it is configured
via Qubes RPC service.
At GUI startup send monitor layout to the VM.
