Merge pull request #322 from mojotech/cs/tests

Add offset to span test
Merge pull request #323 from mojotech/cs/tests

Normalize span test
Merge pull request #324 from mojotech/cs/tests

Add column test
Merge pull request #325 from mojotech/cs/tests

Add shift test
Add unshift test
Remove IE7 support for edit
Add edit test
Update css-diff to handle whitespace diffs
Refactor pass on test implementation