Explicit latitude/longitude settings for weather forecast lookup

[vielmetti]

If the geocoder API is over limit (see #54) you get an error rather than a forecast.

Handle the case where you know exactly where you are already, and pass in the latitude and longitude directly to the API, e.g. support queries like so:

weather --latitude 42.27756 --longitude -83.74088

which will give you Ann Arbor, MI, or the same output more or less as

weather -l "Ann Arbor, MI"

I have a work in progress to do this - the only small hitch so far is that the output routine counts on there being a nice name for the location.

[vielmetti]

Closing as wontfix, not a bad idea but not necessary.