added .write function to ShapeList
added check for consistent shapes
added versioning code and a version #
added version stuff in setup.py
uses __builtin__.open
Merge branch 'version' of https://github.com/keflavich/pyregion
workaround matplotlib backward-incompatible change. closes #15.
Fix print statements in demo_print_region.py for Python 3
Declare that pyregion supports Python 3 in setup.py