RFC: Added AnnotationPoints, AnnotationLines

This is working, but I'm not really happy with the points implementation.  

1. It's probably slightly too complicated.
2. For my needs, it would be better if the points did not scale with image size.  

Anyway, I wanted to put it up and get feedback.  I'll try to work on it again a little later, but it suffices enough for me now to get some work done with it.