Allowing users to override the default connectivity in locations.ini

So many whitespace changes...I'm sorry.  Let me know if you want me to resubmit without those.  

This is based on the gist discussion we had:  https://gist.github.com/jklein/5777553.

I found that `empty` accomplished the same goal as `array_key_exists` plus `strlen`, and it's much more readable, so I went with that.