Abc simple

[cdonovick]

When building the FP library I ran into some annoyances in how I was binding types with getitem. I had been using lookup tables in the metaclass to store information however, this meant the info was not available until after class construction was complete. To avoid this I reserved the name _info_ and inserted the required information into the the namespace.

This pull requests does something similar for the other metaclasses. This in many ways simplifies the metaclasses / classes as there are no more crazy redirects through weakref dictionaries. Instead information is stored in _info_ for types constructed by AbstractBitVectorMeta and _fields_ / _field_table_ for those constructed by BoundMeta.

This should have no effect on user code unless it was using one of the reserved names.

Both peak and lassen pass travis with this branch:
https://travis-ci.org/phanrahan/peak/builds/538426697
https://travis-ci.com/StanfordAHA/lassen/builds/113493648

[leonardt]

LGTM, I didn't follow the changes in full detail, but at a high level it makes sense and the tests pass. It seems like it simplifies the overall logic by removing indirection so it should make maintenance easier.