move out xib files from Resources to Classes

This should allow hedgehogs to still move freely after trapping other hedgehogs in a portal loop.

Move the crystals to sprays to reduce the regularity of the land texture

Add Cave theme

(a lot of) ooops

- Frontend: don't pass /script for missions - Engine: try to load script for map (not tested)

Tiny cleanup

the retina infection keeps spreading...

be a good memory aware citizen

make the missions/trainings start

first pass for implementing missions/training selection on ipad (not yet running)

hm. probably should set both

Basic test implementation of an ice flag. Allows for slick parts of terrain. Intended for ice gun, or "ice" mask on portions of land objects. In this test variant it is triggered on girders/objects/bridges of the snow/christmas theme, or on a map that uses blue as a mask colour. Probably needs sheepluva's slope detection to make slopes more slippery to climb.

on ipad2 and above animate the little hogs on game config and fix the hat display imaging

little changes and fixes to the previous commit

headers cleanup, converted some function-only sources into proper class method files, more use of OOP power, removed some 'respondsToSelector' calls, moved defines into their own header, more use of objc categories