Correct Search API endpoint

When you do a get request with the 'search' parameter it will point to the wrong endpoint (https://api.twitter.com/1/search), but the correct endpoint is https://search.twitter.com/search. 

While the Search API is not necessarily used through OAuth, I think it's best to include this different endpoint in the class, and switch to it when needed, to prevent any debugging frustration and unnecessary/unsupported API calls to Twitter.