Fix version of Mocha to 1.21.4
Merge pull request #140 from alancutter/updateMocha

Fix version of Mocha to 1.21.4
Identified the cause of this bug (issue 131).

Need to fix, but might want to do some refactoring at the same time.
Fixed bug (131). Needs tests.
Started adding a test for timing functions in constructed Animations
Make test pass
Whitespace
Make tests pass after rebase