Manual merge of fix point and linear/new-stuff

Not Ready to Merge
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This type checks and includes all of the work @byorgey  did
on fixpoint. This should replace the fixpoint branch but please
don't delete fixpoint yet as it may have valuable comments that I 
missed.

Next
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   - Contextualize Trace (done).
   - Add `Transformable` instance for `RTree` (done).
   - Possible `Transformable` instance for `QDiagram`s (done).
   - What to do about `Measure` in the `Context`.
I'm not sure how this definition can make sense after we add `Measure n` to the `Context`? This diagram will not be a function of the Global to Output or Normalized to Output transforms.