DIRAC v6r13 release

[Andrei Tsaregorodtsev]

The new DIRAC release v6r13 is ready. The main new features in the new release are
the following:

- Support of the IPv6 sites
- New service in the Framework system for static monitoring of all the DIRAC components ( services, agents, databases )
- Using the FTS3 services for data transfers via the FTS3 REST server interfaces
- Reworked Request Management system with the database access done by means of the SQLAlchemy database client
- Significant changes in the Data/Resources Management to encapsulate physical access URL management in the Storage plugins
- Introduction of new plugins for the TaskManager in the Transformation system. Possibility to limit certain job types to a particular
  list of sites
- More uniform description of the computing resources with the introduction of BatchSystems classes to be used by generic
  SSH and Local ComputingElements

  For more details on the changes see the release notes available in the standard place.

  Most of the changes are trasnparent for the users. However, notes on the changes necessary to be done to upgrade
v6r12 installations to v6r13 can be found here.

  Please, report all the encountered problems with the new release
to the DIRAC forums. The encountered bugs are to be reported in the DIRACGrid
project issue tracker of the Github service https://github.com/DIRACGrid/DIRAC

  Cheers,
  Andrei

P.S. Sorry if you get this announcement twice