merge

Add square check to shotgun. This a minor optimisation that might sidestep a bug on iOS/Android. Still need to find out why the bug is happening though

Break visual gears list up into 4, to avoid iterating over entire list to draw a single layer. Also fix error in tag zoom.

Make it a lot harder to cheat with typical random crates. This also means that crates will vary even if map has the same seed (hog positions of course will be unchanged).

At mikade's request, expose screenheight/screenwidth and allow setting tag zoom level

Properly implement slot, connect signal from the object which actually sends it to the slot

Check for dX too