Merge commit '0.1.1' into develop
added a model and quickcheck tests
ported the haskell quickcheck properties to python
Added an implementation of the original algorithm to prove that the model is correct
Merge commit '0.1.2' into develop
moved the test_requires around to make them install correctly
fixed the 3.x tests
fixed a bug where repeated crops were not relative
bumped version
Merge branch 'release/0.1.3'