Added .gitignore
Updated all scripts to use application-auth instead of user-auth

Updated all scripts to use application-only authentication:

  https://dev.twitter.com/docs/auth/application-only-auth

instead of user-authentication.  The application-only authentication
rate limits:

  https://dev.twitter.com/docs/rate-limiting/1.1/limits

are (currently) higher for accessing the 'statuses/user_timeline' API
endpoint (300/window for applications vs. 180/window for users).