Continuous representations in sympy.physics.quantum, part 2

NOTE: Updating this based on recent emails on the Sympy list. What is left to do on this is:

TODO - 

- [ ] Finish rebase and fix broken tests
- [ ] Review API 

As I'm sure you've noticed my time constraints have meant that I just have not been able to get this done. Every time I try to start back up with a rebase I get caught up and it ends up slipping again.

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This pull request is my last official GSoC pull, though I will continue spending next week adding some additional features I'd like to see, as well as working out the kinks in this PR.

Many things are accomplished here, namely:

* Cleanup of outstanding issues from my previous PR
* Change the rest of the quantum computing classes to follow the new conventions for representations introduced by this work. 
* Introduce a complete set of steps for continuous representations, including integration and correct application of operators

If you look at the examples in piab.py, I think it will give you a real sense of what the project has accomplished. While I haven't been able to implement as many example systems as I wanted (yet), you can do some very cool manipulation of expressions in continuous bases, including computation of expectation values.