Updated Animation to optionally use SIMD

SIMD structures can now be used to calculate bone transforms.
Updated Animation to optionally use SIMD

SIMD structures can now be used to calculate bone transforms.
Rebased, renamed SIMD views to match John's naming convention
Merged
Set up UI for swapping between SIMD and non-SIMD code paths.
Merge pull request #90 from toji/skinning

SIMD Posing + UI