SkeletonState change attribute name.

New name is more meaninful
Fix y axis criteria.

Now every bone y axis points in the same direction
Added equivalent method to Node class.
Added PCL

PCL is Point Cloud Library, with this software we have access to advance
point cloud algorithms.
Fix optimize rotation in Node class.

It was failing because the rotation can only be optimized if the node has one or
doesn't have any children.
Improved SkeletonMixer with legs.

SkeletonMixer now also mixes the leg sizes of right and left legs.
Correct root rotate all frames and small fix on SkeletonMixer

Root rotate all frames was not doing with the node rotation axis.
SkeletonMixer now also resets the per frame offset to 0.
Fixed how y axis is calculated for root node.
Fixed bugs of SkeletonMixer

To calculate the distances it was using the sum of the squares but that not
matematically correct. Also in the leg fitting it was not calculating correctly
the mean of the bones.
BodyFitter fit_head_and_back now can recover from some errors

Before it would need the three bone positions to work, now if it fits as many
as it finds.
Updated scale factor in BVH files.

Previous units were way too big for a dog, so bvh file is now half the size so
we adjust the scale factor so in the render the size is the same.