Update mentions of database_prefix to table_prefix

In the docs and shell prompts you mention database prefix, but in WP Config its referred to as $table_prefix, I updated some details ~ feel free to do with as you wish :+1: 

Otherwise, :100: great plugin, it does exactly what I wanted it to do. I tested with OSX + MAMP PRO, so feel free to tag me if you get any issues with a similar env.