Make stack traces work with the noConflict method of including jQuery
Stack traces should only be disabled if ENABLE_STACKTRACES is True
Don't append call until duration has been set
Merge pull request #1 from c-oreills/master

Fix for concurrency sads ('duration' key not always set)
Merge pull request #3 from colinhowe/master

Make stack traces work with the noConflict method of including jQuery