Implemented skeletal animation blending.

Added blending across multiple animations to better support transitions
between different animations.
Added an example character controller demo.

Show skeletal blending transitions between idle and walk cycles.
Changed johnson's texture name.
Merge branch 'master' of https://github.com/insominx/three.js
Add quick and dirty fix on non-looped animation.
Updated three.js and three.min.js.