* Fixing issue where Scheduler::unscheduleAll() would not unschedule functions scheduled with Scheduler::performFunctionInCocosThread.
* Removing clear of _functionsToPerform from unscheduleAll, based on code review feedback. Adding a function removeAllFunctionsToBePerfomedInCocosThread, which will remove all pending functions scheduled with performFunctionOnCocosThread.
* Adding test case for Scheduler::removeAllFunctionsToBePerformedInCocosThread
* Adding proper cleanup code to Scheduler test for SchedulerRemoveAllFunctionsToBePerformedInCocosThread