Updated TimeLineSettings to Use since_id

Per our discussion, I updated the timeline settings to take since_id.  This will allow me to provide a minimum/since "tweet" id that I want to get data from.  

The suggestion you had made to update searchsettings wouldn't have worked since per your comment earlier Twitter API doesn't allow one to search based on user for that you have to use timeline and timeline doesn't provide a way to get Tweets based on date, you have to use since_id.

Look it over and let me know what you think. 

Dhaval