Remove unused code and fix some stylistic issues.
Really basic coverage support for test-runner
Remove parent argument from TimedItem constructors
Add and use a utility for abstract methods
Remove dead code
Fix *Group.clear
Merge pull request #231 from web-animations/coverage

Really basic coverage support for test-runner
Merge pull request #232 from dstockwell/dead-code

Remove parent arguments and dead code. Simplify abstract methods.
Merge pull request #221 from dstockwell/clean-up-testharness

Remove unused code and fix some stylistic issues in testharness_extetensions/timing
Merge pull request #233 from mithro/fixing-t0-problem

Refactor how timing code works.
Log when the callbacks are called for easier debugging.
Call the callbacks in the same order they where added.
Merge remote-tracking branch 'up/master'
Merge branch 'callback-order'