Remove --scrape mode

[edsu]

Twitter's ToS pretty explicitly forbid what the --scrape option does. I'm removing this functionality so we play nicely:

access or search or attempt to access or search the Services by any means (automated or otherwise) other than through our currently available, published interfaces that are provided by Twitter (and only pursuant to those terms and conditions), unless you have been specifically allowed to do so in a separate agreement with Twitter (NOTE: crawling the Services is permissible if done in accordance with the provisions of the robots.txt file, however, scraping the Services without the prior consent of Twitter is expressly prohibited);

Plus it never seemed to work terribly well, and complicated the code a bit.