Add support for email subject prefix
Merge pull request #351 from rantav/email-prefix

Add support for email subject prefix
Create lock pid directory with global write permissions.
Merge pull request #358 from spotify/lallea/lock_dir_777

Create lock pid directory with global write permissions.
Fix marking a task as PENDING while it is still running - in the history DB
Update the task in the historydb only if there was a change in status, prevent multiple updates of the same status
Refine the check for writing into the history db. If the status is PENDING - write no matter what the value of task.status is - since it's the default value
Merge pull request #344 from rantav/fix-historydb-repending

Fix marking a task as PENDING while it is still running
Case insensitive job tracking

Required for new cascasding version
Merge pull request #359 from SamRozen/samuelr/hadoop

Case insensitive job tracking
Merge branch 'upstream_master'