ENYO-2744: add pluggable enyo.ready.require/provide mechanism to delay r...

...unning app code until after application prerequisites like external font loading are complete.

Update test suite to use enyo.ready() for running unit tests, then add a require/provide pair to delay starting tests.

https://enyojs.atlassian.net/browse/ENYO-2744

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)