* optional default blend argument, use for better leg & arm defaults
* way to define arbitrary options for bones that can then be passed to the generator function, only used to set elbow target parent at the moment.
- updated delta not to remove a bone
- spine and neck rigs interpolation bones are now axis aligned to the control bone
- palm tag is expected on the pointer finger rather then the wrist
- operate on bone children first working up the chain (not essential but more pradictable)
original bone names cant be changed anymore but this means the bones can be re-parented without confusing scripts that run after the rig is modified.
support for defining a bone to have multiple types and automatically blending between 2 generated rigs