X-DCOP-ServiceType -> X-DBUS-StartupType
Change name into desktop file (now dcop is dead we use dbus)
I keep compatibility with 'X-DCOP-ServiceType'
X-DBUS-StartupType: name found by David (better than X-DBUS-ServiceType)

Rename a lot of reference to dcop.

Patch ok'ed by David.

Update doc.

Rename DCOP_* enum to DBUS_*

I will continue to rename reference to dcop -> dbus

I will change all desktop file which have key X-DCOP-ServiceType to X-DBUS-StartupType