use non-commercial YQL for woeid lookups

Note: I don't expect this to be merged immediately, but I wanted to start a conversation.

I started looking into Issue #6 for getting a woeid by lat/lng and didn't see an easy way to accomplish this with the woeid endpoint you were using (I later found it and replied to the issue).

Doing more digging, I found Yahoo has changed their API several times and seem to be pushing [Yahoo BOSS[(http://developer.yahoo.com/boss/geo/) now. One of the options is [Free non-commercial YQL lookups](http://developer.yahoo.com/boss/geo/docs/free_YQL.html) which allows you to do lookups by name, zip, lat/lng, and more and is pretty flexible.

So I took a stab at implementing that. The nice thing is that you don't need an APP ID and it is free. The downside is that you are limited to non-commercial use and 2000 requests per day.

Questions: What are your thoughts on using this endpoint? Is it worth replacing the default endpoint given the limitations? Is it worth implementing it as an alternate endpoint that is used if no APP ID is provided?

Thanks