Combine multiple operations of the same type.
Group db opers by type prior to combining.
Improve efficiency of db_oper construction.
Fix accidental discarding of db_opers.
Fix bulk commands. Reduce frequency of commit operations.
Merge remote branch 'upstream/master' into rundb-combine-oper
Remove redundant variable setups.
Merge remote branch 'upstream/master' into rundb-combine-oper
Removed "ready" and "not ready" printing from clock triggered.
Added a final connection commit just in case.
Merge pull request #623 from arjclark/rundb-combine-oper

fix delayed run-db thread shutdown