Support @DisallowConcurrentModification.  Support multiple trigger on on...

This update fixes/addresses the following issues

   https://github.com/michaelklishin/quartz-mongodb/issues/1
   https://github.com/michaelklishin/quartz-mongodb/issues/51
   https://github.com/michaelklishin/quartz-mongodb/issues/52

And adds to the fix already in place for

  https://github.com/michaelklishin/quartz-mongodb/issues/48

In addition it also overrides the use JOURNAL_SAFE with FSYNCED when writing lock records to the DB.