Blender Git Loki

Collada refactor: Added meaningful Constructor for BCAnimationSampler

The processing was unnecessarily split into creating the Sampler
and initialising it later. This can safely be done in one go
within a Sampler constructor

Also removed the not needed reference to the Sampler inside
the AnimationExporter instance. The Sampler is now a simple
local variable in AnimationExporter::exportAnimations()