Added engineOnly flag to disable loaders (when all you need is instrumentation
Updates dist
Fix copy+paste typo
Added testReadyCallback attribute to allow extra binds just before the tests run
If you pass a function to 'testReadyCallback' you will be provided with a callback to call at the end of your extra code.

If you pass a string, it will be executed and then the test runner code will be executed (sorry, no async with string based)
Update dist
Fixed undefined/null check on testrunnercalbback code
Merge pull request #235 from alex-seville/master

Added engineOnly flag