add OperationTimer
add timer methods in Observable.java
add OperationDelay
copy delay test by @jmhofer

source: https://github.com/jmhofer/RxJava/blob/e9027293dadf846b64f62e91da7c5c5850ed76f5/rxjava-core/src/main/java/rx/operators/OperationDelay.java
add delay methods in Observable.java (copied those by @jmhofer)

source: https://github.com/jmhofer/RxJava/blob/18d40522bb19f80c0ff8d4079bcb925742efecf4/rxjava-core/src/main/java/rx/Observable.java
make OperationDelayTest test Observable.delay instead of OperationDelay.delay
More precise marble diagram for the case when zip() takes an Observable that emits Observables
Lock-free subscriptions
Fix for buffer not stopping when unsubscribed.
Merge branch 'master' of https://github.com/Netflix/RxJava into docs
* corrects grammar of sequenceEqual() javadoc
* updates link to wiki description of count()
* adds sample(sampler) marble diagram/wiki link
* adds longCount() marble diagram/wiki link
Merge pull request #596 from akarnokd/BufferFix1

Fix for buffer not stopping when unsubscribed.
Merge pull request #597 from Netflix/docs

Javadoc updates (longCount, sample(sampler))
Merge pull request #576 from samuelgruetter/delay2

Timer and Delay
Merge pull request #593 from akarnokd/LockFreeSubscriptions

Lock-free subscriptions
Migrate Schedulers to rx.schedulers package
Organize Imports - Migrate to rx.schedulers for src/main
Backwards compatible deprecated rx.concurrency classes

These will exist for a few releases to allow people to migrate from rx.concurrency to rx.schedulers.
rx.concurrent -> rx.schedulers for Android and Swing modules
Migrate code to use rx.schedulers instead of rx.concurrency

Unit tests passed before and after (did change in multiple steps to assert unit test pass against rx.concurrency before migrating to rx.schedulers).