py3k compat for setup script
Basic Py3k syntax fixes
__future__ imports everywhere except in the tests.
Iterators now follow py3k iterator style. Fallback to old py2k style exist.
Fixed some more types for Py3k.
Full py3k compat in the tests.
Py3k classifiers  in setup.py.
Travis now tests on Python 2.6, 2.7, 3.3, and 3.4
Updating docs.
Fixing PyQt incompatibility.

I am not sure if the inconsistency is due to Python or PyQt version
differences so it might need to be adjusted again at a later point.