Shapely Py3k
compat: Removed bytes() compat
compat: Use if py2 instead of py3

Future compatible with a possible py4
setup.py: Moved shapely dependency back to tests_require list

Shapely is not a requirement, GeoAlchemy 2 work fine without it
setup.py: Import cleanup
Merge pull request #71 from Turbo87/shapely

Shapely Py3k support #2