New stream parameter - location

[blackrosezy]

Hi, first of all thank you for this great program. I have a suggestion if we can have a new location parameter for streaming. So it will become something like this :

t stream search "#G20" location "-122.75,36.8,-121.75,37.8"

This is useful for some users (e.g PHD researcher) to limit the streaming by geographical area.

Here is the documentation for the API:
https://dev.twitter.com/streaming/overview/request-parameters#locations

We can also improve the location parameter by supporting predefined ISO 3166-1 alpha-2 country codes. An example for Australia:

t stream search "#G20" location AU

Reference:
Visualization geographic bounding boxes:
http://bl.ocks.org/hugolpz/6391065