The Orange class passes all unit tests

[Edward K. Ream]

The latest round of work on leoAst.py is complete. This also is a big step towards completing #1440, unify the ast and token worlds.

Today's work also completes #1474: Better coverage tests for leoAst.py. Integrating coverage testing with unit testing has completely changed how I think about programming.

I'll say more in other posts.

Edward