Introduced "AsyncTask.Compare/CompareCore" methods
Introduced "AsyncTask.WeighAgainst/WeighAgainstCore" methods
Implemented "AsyncTaskComparer : IComparer<AsyncTask>" class
Implemented PrioritizedAsyncTask, InconsequentialAsyncTask classes
Added failing test case TestTaskQueuePreProcessing with right expectation
Implemented "DynamoScheduler.CompactTaskQueue" method
Implemented "DynamoScheduler.ReprioritizeTasksInQueue" method
Added comment for "DynamoScheduler.CompactTaskQueue" method
Addressed review comments
Removed unwanted "DynamoScheduler.CompactTaskQueue" method
Merge pull request #2773 from Benglin/Revit2015

Cross merging master changes into Revit 2015