Fixes

-Renamed the WorkerProgress class to NodeManager
-Error handler no longer removes jars from the database if they are still in use by other jobs
-The NodeManager is now responsible for deleting local jar files when they are no longer in the db
-The NodeManager now reports recource (cpu, ram, disk space) info to the database every 10 seconds

Signed-off-by: Bennie Leonard <bennie.leonard@gmail.com>