Further fixes to kDebug:
* Since KConfig works without a main componentdata nowadays (auto-created by kglobal), make kDebug work
pretty much the same in qt-only apps as in kde apps, including obeying kdebugrc settings. The only difference
is that area 0 (and unknown areas) are called qAppName() rather than main-component-data-name.
* Update that name when the main component data gets created, even after early kDebugs.
* Make the handling of unknown numbered areas more consistent (using the settings for area 0)
* Complete unittest for the "no component data" case, in a separate program called by kdebug_unittest.