Improvements from Mike

1. Config option to specify port on which to run.
2. New command 'whatcanibuy' which converts your dogecoin balance to multiples of our saved units so you know what you can buy.
3. Improved documentation.
How does this work? `sentence` is an undeclared variable here. Also, since this is the last statement of the method, you could just return the string, no need to set it to a variable.