cmake: Drop image and mixer init and quit check

avoid double applying wind on drill

- Reduce tau value, as suggested in gecko2 paper - Also store games number per epoch

Set gears that go off map to gmDestroy instead of collision, disable morewind for no-gravity gears, restrict application of wind to gears that are already moving and not colliding.

Merge

Added tag Hedgewars-iOS-2.0 for changeset a0163b8302c5

Closed branch ios-rus-localization

this should fix travis build

about: Update SDL2 names and drop old version check

merge sdl2transition changes