Connection Pooling Min and Max Setting

I've added the ability to specify the connection pool min and max sizes since the default C3P0 settings aren't
really suitable for all production applications.

Commit comments:
a connection pool min and max, the defaults
for min and max map directly to the defaults 
that come from the C3P0 library

also filling in tests for the db/connection-pool
function asserting that the min and max settings
work as well as the defaults