4295: First pass at more efficient database utilization.  A few tests fail.
4295: Fixed tests
4295: Add test that large numbers of events are handled efficiently and correctly.
4295: Abort on NoMemoryError
4295: Fix typo in comment
4295: Use EventMachine::schedule when there is potentially more events to send instead of pushing an event to the channel (which wakes up all listeners).
Merge branch '4295-efficient-websockets' closes #4295