Wrap custom effect with animation in source
Move underlying player construction to maxifill-player.

Now `element.animate` is just `timeline.play(new Animation(...))`
Move element.animate to animation-constructor
Lint.
Merge pull request #246 from dstockwell/pass-anim

Wrap custom effect with animation in source
Players should be constructed in idle state

Fix issues encountered
* play() should not set a start time
* cancel() should not nullify the source
Use element.animate in "Getting Started"
Add tests for play() and reverse() not setting start times
Remove double ticking
Merge pull request #247 from dstockwell/newidle

Players should be constructed in idle state
Merge pull request #248 from dstockwell/newidle

Remove double ticking
Merge remote-tracking branch 'web-animations-next/master' into HEAD
Add build artifacts from be6e1a155ee146a5b273aa70cccd6727dbc7f420