Added support for additional parameters

Hi, 
First of all, thank you for this module!

I needed to send some extra parameters to Yahoo's API, so I refactored the module to support that. 
Basically I changed the signature of the methods and instead of expecting only 'count' parameter, each method now expects to receive an object. the object may contain any parameter and will be serialized with 'q' into one query string . 

Let me know if something is not clear,
Thanks again.

Asaf