Add icecrusher (WIP) [DO NOT MERGE]

[tobbi]

My WIP ice crusher which is working quite well by now.

Things to do (some optional):

• Make sure eye movement points directly to Tux and not away from them
• Spawn particles when the crusher hits the ground?
• Investigate whether it's possible to add the different sizes in one .tscn file
• Ice crusher is currently too big for the editor image. Resize editor images automatically.

[tobbi]

Also, it should probably not hit when Tux is in edit mode. Speaking of which, why do we display Tux in edit mode anyway? We have a spawnpoint that we should obey.

[qwertychouskie]

Tux moves so that you can easily test a portion of the level without having to move the spawn point, same as Mario Maker does it. The spawn point is used when the level is restarted using the pause menu, or (in the future) when playing the level normally ("Play Game").

[Alzter]

Maybe if you added an export variable for icecrusher size and then made multiple icecrusher enemies, or made a popup to change the size?