Revision 38180

From Gerri:
Fix a few issues in SQL PROOF monitoring:
- In TSQLMonitoringWriter::SendParameters, drop ''' around field names in
  the INSERT string; also use TString::Format(...) instead of Form(...)
  where relevant;
- In TPerfStats:
  - call 'proofgroup' instead of 'group' the field with the PROOF group
    (interference with the 'group' keyword in SQL);
  - add new field 'querytag' VARCHAR(64) with the unique query tag
  - in WriteQueryLog fill also the field 'totevents'
  - in PacketEvent, add switch to control whether to send te information
    to the monitoring system on per packet level (may be too much for SQL).
    The switch is called fMonitorPerPacket and it is globally controlled
    by the rootrc variable 'Proof.MonitorPerPacket' and at
    session level with the parameter PROOF_MonitorPerPacket .