Add unit test for MultiSignalMapper.
Make this file self-contained.
Port MultiSignalMapper away from senderSignalIndex().

Instead, use the method index (which we can freely choose). That's faster
and works with Qt < 4.8 as well.
Obviously it shouldn't be senderSignalIndex() here either.
Merge remote-tracking branch 'origin/2.0'

Conflicts:
	tests/CMakeLists.txt