working on diffing algorithm
Move diff tests to tests/ folder
Merge branch 'master' into diff
find_candidates() works
Adapt find_candidates into an lcs() function
Add another test case for lcs(), make it pass
Write diff_points().
Implement diff()
Fix check_match
Fix create_grid
Fix flake8 problems in diff code.

tags: #stylefix
Merge pull request #58 from tarmstrong/diff

Diffing algorithm