javadoc improvements (groupJoin, groupByUntil, timestamp w/scheduler)
Merge pull request #569 from Netflix/docs

javadoc improvements (groupJoin, groupByUntil, timestamp w/scheduler)
Operation Sample with Observable v2
ObserveOn fix for observing the same source on the same scheduler by two different observers.
Removed Opening and Closing historical artifacts.
Fixed scala compilation error.
remove package rx.lang.scala.util since all its contents were removed
remove import rx.lang.scala.util._
Merge pull request #1 from samuelgruetter/OpeningClosingRemovedSam

remove package rx.lang.scala.util since all its contents were removed
clarify documentation on cache()
Reimplement the 'SequenceEqual' operator using other operators
Fix the 'null' issue in the default equality
Update ObservableHttp.java

Removed pesty dangling </p>
Fix Concat to allow multiple observers
Operation LongCount
Merge pull request #568 from jloisel/master

Use lock free strategy for several Subscription implementations
Merge pull request #571 from akarnokd/SampleWithObservable2

Operation Sample with Observable v2
Merge pull request #572 from akarnokd/ObserveOn3

ObserveOn fix for observing the same source on the same scheduler by two...
Merge pull request #573 from akarnokd/OpeningClosingRemoved

Removed Opening and Closing historical artifacts.
Merge pull request #574 from samuelgruetter/cache-documentation

clarify documentation on cache()