Last call: connection pooling patch

I've finished up my work on connection pooling, patch is here:

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/936-connection-pooling

Please try it out, comment, etc. and give +1s if you want. Any
comments on default pool size (5) or default wait timeout (5 seconds)?

Note that this is probably not the last word -- the patch still needs
to be battle-tested, but we expect that to be done once the patch gets
merged into edge and any necessary fixes will follow.

Cheers,
/Nick