Microsoft-CISL/REEF — pull request #764 by markusweimer (2014-04-23 00:56:35+00:00)
Title: Refactoring of the YARN resource manager

**Features added**
* Closing #759: Drivers can now have `com.microsoft.reef.runtime.yarn.driver.YarnContainerRequestHandler` injected to file YARN resource requests in addition to also being able to use REEF requests.
* Added a TrackingURLProvider to the YARN runtime

**Refactorings**
* Split YARNContainerManager into smaller classes as opposed to one big one.
* Renamed `com.microsoft.reef.runtime.yarn.master` -> `com.microsoft.reef.runtime.yarn.driver`
* Worked with IntelliJ's code analysis to improve code quality.

**Improved shutdown logging and behavior of the Driver:**
* Added logging of an idle shutdown
* Added optional logging of the callstack to DriverStatusManager.onComplete()
* Removed a case in which we would trigger DriverStatusManager.onComplete() twice