#21 Use some key frames for all 3D animations

[Julien Gouesse]

There are currently a few animations that aren't based on key frames, for example the one of the weapons used by the player. Its own animation system is basic and too much rigid. The key frame controller of Ardor3D is able to interpolate the meshes of the key frames to drive the animation smoother. The source code would be easier to maintain if all animations used key frames and it's still possible to convert custom animations to key frames by creating several meshes and a key frame controller.