[Animation] Define animations from YAML

[PxlBuzzard]

We need some way to define animations in yaml. I don't know what form that will take yet, but I have a suggestion of how it might be done:

---
Name: Foo
Script:
    ClassName: foo.bar
Mesh: foo
Material: bar
Animations:
    Idle: foo_idle
    Run: foo_run

[tmr9209]

I agree this is important, yet this should be for the next milestone or after I add support for multiple animations. Currently it will automatically do the idle animation and use basic play/pause/stop. There is no benefit to .yml for animation currently.