Issue #2025109, comment #3: hook_requirements() needs to return at least an empty array if implemented to prevent fatal errors during installs from a profile

Issue #1977950 by cdenneen, joachim: Added options for showing retweets and replies in Twitter Block Box.

Issue #917460 by ccarigna, mrfelton, jec006, joachim: Added twitter pull block type for Boxes module.

Hardening security by filtering the output of Twitter API, just in case Twitter lets through something XSSy (very unlikely but still)

renaming twitter_pull_block_info to twitter_pull_block_data since hook_block_info() is a reserved name (hook) in D7

Changed number of tweets limit to reflect Twitter API, and added limit arguments in API calls. Added detection of request rate limiting. Fixed CSS to prevent stretching profile images. Improved compliance with coding standards.