Animation support

[michalbe]

Since basically every 3d software can export FBX format, let's use it in Cervus as well. The MORPH component could probably be used in here, but further research is required to confirm that.

Questions & concerns

• Maybe md5 would be easier to work with?
• The easiest would probably be simple JSON model format from this Online 3D Converter, it exports FBX animations and bones to JSON (tested on Mixamo models)

Old description

• Clean up the voxel animation code
• Add support for multiframe animations from Magica
• remove the mesh builder and leave just the parser (as a module maybe?)
• optimize animations (diff between frames?)

[michalbe]

I feel like this ticket should be divided into two - one for Animation component, and second one for the model loader that converts Assimp2Json format to the one expected by our shaders.