Provide Observable.timestamp(Scheduler) to be used in the tests.
Added support for custom functions in combineLatest.
Fixed testSingleSourceManyIterators
Rename `bind` to `lift`

As per discussion at https://github.com/Netflix/RxJava/issues/775#issuecomment-33075742
`Observer` becomes `Observer implements Subscription`

As per decision at https://github.com/Netflix/RxJava/issues/775#issuecomment-33075742
Move Observer factory methods to Observers

Follow same pattern as rx.observables, rx.schedulers, rx.subjects, rx.subscriptions
Subjects Fixed
Move Observers to rx.observers
Compiling. Unit Tests Failing.

Now that Observer is an abstract class, Mockito is having issues with it so unit tests are a mess.
Added join
TestObserver
Operator Tests Retrofitted to use TestObserver

- work around inability of Mockito to correctly mock an abstract class
- 15 of 590 tests still failing
587 of 590 operator unit tests passing
Fixed buglet in join binding.
Simplified types for groupByUntil, window, buffer, and empty to use Any and Nothing.
Down to 7 of 893 unit tests failing
Fixed 1 Unit Test - Linked Observer/Subscription where seemingly obvious to do so.
Fix Subject SubscriptionManager

Remove possibility of infinite loop
Clarify intent of unit test
OperationJoinTest - fixing
Ignore JoinsTest.whenComplicated until questions answered