Bunch of cosmetic tweaks to the gamification UI

- submarkers
- removal of margin around images
- addition of a button that pops up the game rules
- automatic popup of game rules on startup works in desktop browser but not in webview, and I have abandoned the attempt to get it to work
    - but have checked in the code in case I need to retrieve it again
- remove all the automatic popup stuff since it doesn't work anyway and is read code