reduce qunit failures on jenkins

* Fixes #1104 (i claim)
* Upgrades qunit to 1.15.0
* Change test syntax to take advantage of qunit-1.15.0:
  * Use per-test "assert" objects throughout
  * Use `test() { stop();` instead of `asyncTest() {` for clarity
  * Reduce use of `ajaxSetup` as a workaround to control test synchronicity