quiz 6.x-4.2

Fixed the following bugs:
- Table prefixing bug on random categorized quizzes. (onfly experienced by those using table prefixing)
- Minor UI text changes
- Removed a couple of php notice bugs
- allow jumping option will now be saved in user settings and default settings(this has been working for those who have upgraded from 4.0, but not for those who installed 4.1)
- Fixed problem with validation errors now beeing shown to anonymous users who are taking quizzes.
- Fixed js bug on manage questions and manage results pages
- Fixed ambiguous mysql query for calculate score (This bug only appears in certain circumstances)
- Remove theme specification from quiz node form, it wasn't needed and actualle created bugs with some node form templates.