Dojo mouse tests

dojo/_base/event and dojo/mouse module converted from DOH to Intern.
I found a better way to do this:

https://github.com/bryanforbes/dojo/blob/intern-conversion/tests-intern/functional/behavior.html#L37-L53
https://github.com/bryanforbes/dojo/blob/intern-conversion/tests-intern/functional/behavior.js#L12-L16

When using `waitForCondition()`, the test runner will poll the selenium server over the wire until it is finished. Using `executeAsync()` allows for the test page to signal the test runner when it's ready.