Making customization easier

I pulled everything (except the hidden HTML in the header) that references represent.la specifically, and moved it into the db_example.php. This should make life easier for folks spinning up new locations. None of the text was actually changed, though, so it all still matches represent.la.

I also changed db.php to config.php, because I think it's a more fitting name, given how much non-DB config stuff exists in it.

The zoom level of the map is now configurable, too.

Finally, I moved the config at the bottom of (what was) db.php file, and put it above the Startup Genome config. This should make it easier to find the config that needs changing, if you aren't using Startup Genome or EventBrite.