alien base fixes: phase 1

clean up that mess.
alien base fixes: phase 2

only spawn bases on ACTUAL signing of pacts.
alien base fixes: phase 3

only 8 alien bases at a time.
alien base fixes: phase 4

don't spawn bases on cities, try to spawn them in random locations.
(based on mission zones)
future proofing IDs to use normal person numbers
Request #235 - Alt+F4 to quickly close the game
UI bugs.
Added Mac OS application quit shortcut and changed code to use default engine quitting scheme.
Added Mac OS application quit shortcut and changed code to use default engine quitting scheme.
Fix bad refactor.
Merge pull request #700 from ZehCastro/alt_f4

Request #235 - Alt+F4 to quickly close the game
center camera on explosions and bullet hits correctly
Checking hit position.
Tuning accuracy calculation.
Avoid conflicts:
	bin/data/Language/en-GB.yml
	bin/data/Language/en-US.yml
	bin/data/Language/ru.yml