Remove Y.Get requirement for tests

The tests were flaky and prone to false-positives due to the dependence on
Y.Get, but these aren't Y.Get tests.

For each test, Y.Get.js is stubbed with a function that calls an indicated
callback from the passed config and/or the test case instance. This allowed
for the removal of asynchronicity in most cases, which really speeds up the
test suite as well.

Also added jsonp-tests to jsonp-url unit test page.
Add test for #700

Failing in this commit because the fix isn't in yet.
Preserve base jsonp _format if {callback} found

Fixes #700

The _format method override wasn't testing the input url for the {callback}
token *in isolation* and doing a simple replacement if found. It was testing
for the presence of "callback={callback}" instead. That meant the default
behavior changed for 'http://foo.bar?otherparam={callback}' when jsonp-url was
use()d.
Add jsonp and jsonp-url now that they work
Remove offending apostrophe
Build jsonp-url
Merge branch 'jsonp-url' into dev-3.x