Created and wired an implementation for the throttle operation on Observables.
Ensure static star imports are used for test cases.
No longer using Notification<T> for scheduling throttled events.
Cleaned up imports and removed unnecessary final keywords in the OperationThrottle class.
Fixed a typo the UnitTest class of OperationThrottle.
set up stubs for Scala Observable and its testing
add methods to Scala Wrapper (1)
add methods to Scala Wrapper (2) and find scalac bug
work around scalac bug by removing `extends AnyVal`
work around scalac bug by giving explicit type parameter to Observable constructor
add methods to Scala Wrapper (3) and find interesting questions

They are marked with TODO
add methods to Scala Wrapper (4)
Merge branch 'master' of github.com:Netflix/RxJava into idiomaticscala
add methods to Scala Wrapper (5) (window)
add Observer wrapper to make subscribe(Observer[T]) work
Merge branch 'operation-throttle' of git://github.com/michaeldejong/RxJava into throttle-merge

Conflicts:
	rxjava-core/src/main/java/rx/Observable.java
	rxjava-core/src/main/java/rx/concurrency/TestScheduler.java
Merge branch 'master' of github.com:Netflix/RxJava into idiomaticscala
Operator: throttleWithTimeout

Another take on `throttle` … I believe this matches Rx.Net behavior.

This will wait until timeout value has passed without any further values before emitting the received value.
Operator: throttleFirst

Another take on `throttle` … this delivers the first value in each window.
Update javadoc for throttleLast