Added connection pool sharing

This should allow users to share their connection pools with fairly
neat semantics and relative ease-of-use.
New API for the connection pool sharing

This seems to work and passes all of the test cases. Might be slight
issues related to events, but they all seem to be functioning properly
Fixed setup for dbs when not connected

Also, added a lot more test coverage for all of the different events.
refactored one test that wasn't checking a value that would guarantee
correctness.
tests; remove .only
tests; validate db contents
tests; close some test connections