Admin account

I need to decide on the best way to handle password storage -- either leave hashing/salting up to the application and adjust the API or just handle it internally.  Might be nice to do the latter.

`plz.authorize.activation` and `plz.authorize.reset` ended up being refactored into aliases for the same member function.  It makes for some redundant documentation and tests, but I figured I'd leave it in case we extend the functionality in a way that warrants the separation.  It's the same case for `plz.complete.activation` and `plz.complete.reset`.

Also, left out testing for the actual sending of mail for the time being.