NEW: added SiteStatus to facilitate RSS access.
just beautification, removed Id
Avoid python circular import dependency
run-time loader
FIX: isUsableSite returns bool. Added loggers
MySQL conneciton pools using threads
Set autocommit to true
Added transaction support + set connections autocommit by default
NEW: getFileUserMetadata gets also the Directory metadata
The meta data of a file is not enough to get that one file back using
meta data queries, it also needs the directory meta data. Now both the
directory meta data and the file meta data are returned.
[FIX]: site in the job definition is taken into account when submitting

Porting back from v6r8 (tested)
save
CHANGE: Get the allowed plugins from the CS
Under Transformations/AllowedPlugins. Needed for adding a user specific
plugin.
FIX: removed continue that was exiting the loop
FIX: added try/finally to make sure locks are ALWAYS released
FIX?: sometimes the string substitution crashes, and no idea why. This
is a small protection.
CHANGE: Remove checking of plugin validity

This is not needed, and Fed agrees.
save
FIX: replaced threading.RLock with LockRing
Back port fix from r8 wrt proxy-info showing an error when there's no CS
FIX: removed "from DIRAC.Core.Utilities.DictCache import *" from
DIRAC.Core.Utilities.__init__ and redone all import paths to be working
again.