Switch buildsystem from qmake to waf.
Removed qmake .pro files. Updated wscript files regarding unittest.
Add new welcome screen

- Minor UI update

Conflicts:

	tower_defense.pro
Fix unittest building with waf

Unittest building was hardcoding to specific path - it's now more generic.
(and it seems to work)
Merge remote-tracking branch 'origin/master' into waf

Conflicts:
	tower_defense.pro