Adding functionality to include checkpoints.
Creation of classes  pqEventCheckpoint  and pqCheckpointplayer.
With this fonctionality, checkpoints can be  include during the test
Merge branch 'master' of github.com:zoat/QtTesting into long

Conflicts:
	pqCheckpointEventPlayer.cxx
	pqCheckpointEventPlayer.h
	pqEventCheckpoint.cxx
	pqEventCheckpoint.h
	pqEventPlayer.cxx
	pqEventTranslator.cxx
	pqPlayBackEventsDialog.cxx
	pqRecordEventsDialog.cxx
	pqRecordEventsDialog.h