Fix link to current test in test-harness.html
Implement Element.animate
Merge pull request #114 from dstockwell/harness

Fix link to current test in test-harness.html
Merge pull request #116 from dstockwell/element-animate

Implement Element.animate
Use the document load event as the zero point for document time

Also make sure that the document time is null before this zero point, and add a
test to check that the document time is constant within a JavaScript
callstack.

This fixes https://github.com/web-animations/web-animations-js/issues/101