Add Common static library. AH-282
Merge remote-tracking branch 'origin/master' into AH-282_Create_level

Conflicts:
	Client/Client.vcxproj
Move a lot of the game logic to the common project. AH-282
Merge remote-tracking branch 'origin/master' into AH_248_checkpoints

Conflicts:
	BoostTest/BoostTest.vcxproj
	Client/Client.vcxproj