xfrun4 + dbus

[Jani Monoses]

Ok, so there are two approaches so far:

1) patch existing xfrun to optionally use dbus and if no service is 
detected behave exactly as now. This needs minimal changes as seen in 
the patch above. However the advantages only show up when some app 
implements said service.

2) make an xfrun-backround process with all the current code, and add a 
new small process which just calls it. The disadvantage I see here is 
dbus dependency is no longer optional for this feature and needs two 
extra apps besides xfrun itself.

both of these will make the run dialog pop up almost instantly so I am 
fine with putting a patch in bugzilla for either of these approaches.

Jani