Ported Kontact::UniqueAppHandler to DBUS.
Since it's not possible to have multiple objects with the same path in the same process, the solution has changed a bit: all pim apps which are kuniqueapplications and which have a kontact plugin, now use KPIM::PimApplication from libkdepim, which registers an object with a component-specific name.

This fixes all the tests listed in uniqueapphandler.cpp, for the various interactions between kontact and the standalone applications (except for one bug in KUniqueApplication itself, which was wrongly ported to activeWindow()).

Note: you need to update kdelibs trunk or make KCmdLineArgs::saveAppArgs public in your kcmdlineargs.h installed header.