Py3k Fixes Bugfixes

It appears that I had some files installed from fixes that got wiped out before being committed. I tested the new python 3 fixes by pulling and building on my home machine (which was not used to develop the changes) and saw that these commits were missing from #1398.

The Travis-CI tests passed for #1398 because it looks like they only run against python 2.5.

The theano-nose script does not run under python 3 because it uses files in the source tree instead of the build directory. The source contains files that get fixed up with 2to3, but the fixes don't appear until the files are moved to the build dir.

I ran the tests manually on my own machine by cd'ing to the build/lib/theano directory and running nosetests3. After many passes and some familiar looking optimization failures, the tests segfaulted so I can't see what went wrong.

This may merit an issue of its own since I'm not immediately sure what's wrong with the py3 tests.