Added `Observable.timeout` wrappers to scala adapter

Added the four timeout methods on Observable in the Scala adaptor. Note
for the java/scala type interop:
http://stackoverflow.com/q/20912151
Implemented the rest 'merge' overloads
Added unit tests
Replaced 'Thread.sleep' with 'CountDownLatch' to fix the flaky test failures
Merge pull request #720 from hura/master

Added `Observable.timeout` wrappers to scala adapter
Merge pull request #731 from zsxwing/flaky-unit-tests

Replaced 'Thread.sleep' with 'CountDownLatch' to fix the flaky test failures
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
Build with Gradle 1.10.

Required that the IDE plugins also be applied to the root, because of the improved Scala support with the IDEA plugin.
Merge pull request #742 from alkemist/gradle-1.10

Build with Gradle 1.10.
Modified to conform Rx.NET