Change dependency versions to work for 3.1.0-rc1.
BUG / Housekeeping of Widget code:
- TagCloudWidget not wrapped with if(class_exists('Widget')) check for dependency module
- Default titles for RSS Widget and TagCloudWidget not being translated.
- Fixed poor indentation, and excessive line length (scrutinizer errors)
- Removal of several blank 'private static $relation = array()' that added no value
- Missing PHPDoc for widget classes
- Fixed missing EOL and removed closing ?> from php files for consistency