Add SparkJobStatus class.
Return SparkJobStatus for jobs.
Make all jobs return a SparkJobStatus.
Return SparkJobStatus from job scheduler.
Add status to more jobs.
Return value of future in polymer wrapper for openFOlder.
nits.
Merge branch 'master' into git_stash

Conflicts:
	ide/app/spark.dart
Addressed comments.
Move status class to jobs.dart.
Merge branch 'master' into job_status

Conflicts:
	ide/app/lib/jobs.dart
	ide/app/lib/tests.dart
	ide/app/spark.dart
Merge pull request #2670 from dart-lang/jobs_return_status

Spark Jobs now return a status