Cleaning up the way proxy users were added to azkaban.
Adding options to change the number of concurrently running jobs.
Fixing issue where cancelling a blocked job won't result in it getting killed properly.
Adding ant build target to concat all the files.
Cancel does a harder kill now.
Adding common props to the job runners.
Adding sla_tables creation in the update sql.
Merge branch 'release-2.1'