fix problems instantiating mussa.GlSequence

fix problems instantiating mussa.GlSequence
with the switch to shared_ptr in the C++ code the original boost::python
GlSequence was wrong--it needed to be updated from references to shared_ptrs
and boost::python needed to be told that it's ok to have shared_ptrs to
Sequence and AnnotationColors.

And I also needed to tell boost::python about AnnotationColors, not that
I defined enough of a wrapper to use it.