Scheduler quits when createStage fails.

The current scheduler thread does not handle exceptions from createStage stage while launching new jobs. The thread fails on any exception that gets triggered at that level, leaving the cluster hanging with no schduler.
Log exception in scheduler in addition to passing it to the caller.
Code Styling changes.
Merge pull request #219 from sundeepn/schedulerexception

Scheduler quits when newStage fails

The current scheduler thread does not handle exceptions from newStage stage while launching new jobs. The thread fails on any exception that gets triggered at that level, leaving the cluster hanging with no schduler.