Port from KPrinter to QPrinter, remove dependency on KDE4_KDEPRINT_LIBS.

I was unable to test as ligature segfaulted on startup even before I started work.
Normally I wouldn't commit this, but ligature will break on Monday anyway when KDEPrint is removed from kdelibs, so at least this way it builds OK.

Note this is only a partial port as QPrinter does not support printFiles or non-continuous print ranges required for the page selection side-bar. We are currently developing the solution for this and will finshing porting when that is ready in about 2 weeks.