GSoC: week 6: Further Python 3 porting work

Continuing on last week's progress, I've worked on the other exceptions and, with the help of Mateusz and Ronan, we are now down to some 33 test failures and 9 exceptions. I've sent a pull request with my current work, you can see it here; I've agreed with my mentor that sending frequent pull requests is the right path to take. I've been traveling for a few days, but my immediate goal is to bring the above numbers down to zero and get the doctest suite to run (which should point out further errors). The pull request also contains a commit marking all errors with a "FIXME-py3k" in the code, which should hopefully encourage other developers to take a look.

My other goal for next week is to port us to Distribute finally, which shouldn't be too hard. Like last week, the biggest hurdle is the decision on mpmath. Once that is taken care of, I'll see about using py.test again (SymPy currently uses an older fork we made) - this will make testing easier (as there have been quite some improvements since it was forked) and will also help when we finally start using Jenkins as it can export data to JUnitXML (which is handled well by Jenkins). This has the downside of disabling our benchmarking suite, but I've agreed with Ronan that we can keep the old code around until it too can be ported. It's hardly used, so it's not that big of a priority.

Another piece of good news is that the core SymPy tests now run under PyPy, which is the second part of my GSoC project. You can see the relevant issue and star it to automatically get any updates. Thanks to Renato for trying this out and reporting back!