Implemented callbackOnce flag in NodeList.transtion (issue 832)
Added test for callbackOnce flag
fixed formatting in transition unit test
fixed issue with the test, it would always pass if any callbacks were fired
changed the test to increment a counter and using a delayed wait to test
changed wording in unit test fail message
updated HISTORY.md with NodeList.transition optional flag info
Merge branch 'issue-832-trans-end' into dev-master
Update Transition HISTORY.md
Build Transition