Implemented the REST communication mechanism for the user registratin in
DIRAC, modified the Job management method for the DIRAC MultiVO support.
Merge remote-tracking branch 'origin/MultiVO'
Adding PARAMETRIC fields
added Parametric JDL fields
Start Checker implemetation
Merge remote-tracking branch 'origin/MultiVO'
Merge remote-tracking branch 'origin/master' into Checker
Implemented Checker and added fields for Parametric job.