Move towards mongo 2.6 compatibility

NOT A WORKING STATE
Update comment
Use global settings object for mongodb uri
Add new integration test
Save the proxy so it can be closed in tests
Add test for deletes
Fix typo in test specifier
Expose db object and minor bug fix
Add stop method (primarily usable in tests)
Refactor and ensure opsync is properly stopped
Make sure updates are enqueued
Emit 'running' event when Opsync#run() is done
Ensure delete operations are enqueued
Test update queue item is removed on send
Test deletes are successfully removed when sent
Move resetQueues helper to helper module
Test proxy handles inserts correct
Test updates are handled correctly
Test delete operations and fix broken test
Fix path