Implemented the rest 'merge' overloads
Added unit tests
ported groupByUntil function.
Buffer with Observable boundary.
Delay with subscription and item delaying observables.
Window with Observable boundary.
MergeMap with Iterable and resultSelector overloads
Added event-merger overload
Publish and PublishLast overloads
Added variance to selector functions
Debounce with selector
Timeout with selector overloads
Zip with iterable, removed old aggregator version and updated tests
Modified to conform Rx.NET
Fixed issue #737
Replaced MultipleAssignmentSubscription with SerialSubscription
Moved unsubscribe out the gate
modified groupByUntil include the key of the group in the closings function.
Merge pull request #718 from zsxwing/merge-overloads

Implemented the Merge overloads
Merge pull request #733 from akarnokd/BufferWithObservableBoundary

Buffer with Observable boundary.