Add pqTextEdit

pqTextEdit is a text edit that follows what is done for pqLineEdit.
It implements the signals editingFinished() and
textChangedAndEditingFinished().
This new widget is used to remove the pqTextEditSignalEndOfEdit widget.

Change-Id: Ifc247869113e00fd2dd0d868f2fe70d9ac1ab2b4
Add test for pqTextEdit

Modify the QTestApp to allow QString to be sent as keyboard events.
Add a unit test for pqTextEdit.

Change-Id: I31c8c4994a8c7e979ae25b84ebb3f4d5e5143e75