BUGFIX: Replaced method call by attribute access.
Improved unit test.
Completed unit test for OBJ mesh edges accessor.
Added a bit of explaination to the test script.
Changed plange coordinate system to use Vector instead of maya vector.
Renamed 'patch' package and modules and classes to 'model'.
Adapted some imports to 'patch'->'model' renaming.
BUGFIX: changed usage of direction on edge to use properties instead of methods.
Added hash end equality to mesh faces and mesh edges.
Removed some debug printing.
Use 'model' instead of 'patch' in user output messages.
Adapted reloading hack to 'patch'->'model' renaming.