Add a simple testharness runner using mocha

There's probably some way to do this using a karma plugin directly, but
this works well enough for now.
Mark expected failures
Merge pull request #168 from dstockwell/testharness-runner

Add a simple testharness runner using mocha
Steps, not step.
Fixed test too.
Merge pull request #170 from shans/easedKeyframes

Resolved to read specification more carefully in future.
Throw an exception when composite: add is specified
Merge pull request #171 from dstockwell/add

Throw an exception when composite: add is specified
Started fising getAnimationPlayers.html
Got play states right. Wrong types of players is going to be harder to fix.
Remove timing out test for CSS players.
Push maxifill players to timeline