unwrap: Mark root intersection as visited.
unwrap: Rename cython functions.
unwrap: Add more debugging output.
unwrap: Improve function signature for find_branch_cuts_cy.
unwrap: Add masking and borders to find_branch_cuts.

All features are now added. Tests for masked images and images without
wrap_around needs adding.
unwrap: Implement residue calculation from masked arrays.
unwrap: Run tests with wrap_around=False.
unwrap: Rename func ...goldstein -> ...branch_cuts.
unwrap: Move private functions to top of file.
unwrap: Docsting for unwrap_phase_branch_cuts.
unwrap: Docstring for find_branch_cuts.
unwrap: Remove unneccesary parameters.
unwrap: Implement phase integration.
unwrap: Differentiate between edge and cut coordinates.
unwrap: Fix bug in edge coordinates.
more debug output
unwrap: Comment out debug output.
unwrap: Minor cleanup in cython code.
unwrap: Bugfix cut detection logic.
unwrap: Cleanup in cython code.