Add wunderground module
Add wunderground module

This module tries to use as much of the same variable naming conventions
that the ``weather`` module uses as possible, to make transitioning
easier in the future in case we decide to make a base class for all
modules which provide weather data.

An API key is required to use this module, information on obtaining one
can be found in the docstring.

drwahl/i3pystatus,asmikhailov/i3pystatus,ncoop/i3pystatus,fmarchenko/i3pystatus,m45t3r/i3pystatus,Arvedui/i3pystatus,richese/i3pystatus,schroeji/i3pystatus,enkore/i3pystatus,Arvedui/i3pystatus,eBrnd/i3pystatus,facetoe/i3pystatus,eBrnd/i3pystatus,ncoop/i3pystatus,richese/i3pystatus,asmikhailov/i3pystatus,enkore/i3pystatus,teto/i3pystatus,drwahl/i3pystatus,yang-ling/i3pystatus,teto/i3pystatus,facetoe/i3pystatus,schroeji/i3pystatus,fmarchenko/i3pystatus,yang-ling/i3pystatus,m45t3r/i3pystatus