Fix the tutorial to be able to do it with Qt5

[parkouss]

For now, the tutorial says that funq-server does not works with Qt5, which is wrong!

Maybe the provided player_tester sample application is not compatible though - so we need to make this compatible if needed, and fix the documentation: http://funq.readthedocs.org/en/latest/tutorial.html

[parkouss]

Fixed with 407ff9c.