Add unique_rows function
Add test for unique_rows
Add unique_rows to util/__init__.py
Remove repeated coordinates before computing convex hull
Unique rows after getting the pixel corners
Move code comment to appropriate line
Add (previously) pathological qhull test case
Add test to unique_rows for discontiguous arrays
Ensure array input to unique_rows is contiguous
Add note describing array copy if discontiguous
Add docstring note explaining coord use case
Merge pull request #672 from jni/chull-fix

Convex hull fix