Add more error detail when database connection fails

[burkemw3]

I had trouble getting the database connection to work, and I added some more output about why.

[benkeen]

Thanks, Matt. I've just merged it into trunk, which is an incomplete version of the upcoming 3.0.0 release (still a ways off yet).

• Ben

[stoneyv]

I see a very terse error message for a failed mysql connection in Chrome developer tools and IE on a git clone of branch master from 2012-12-30. ( I have 2.3.9 working on localhost on both {Ubuntu 12.04 Apache2.2.22,PHP5.3.10, MySQL 5.5.28} and {Win7 / Wamp Apache2.2.22, PHP 5.3.13,Mysql 5.5.24})
Port error: Could not establish connection. Receiving end does not exist. miscellaneous_bindings:235
chromeHidden.Port.dispatchOnDisconnect miscellaneous_bindings:235
Failed to load resource: the server responded with a status of 404 (Not Found)