Various tweaks to UI

- Moved js, css and images into sub-folders
- Added various bits to header to improve IOS experience
- Added icons to footer navbar, removed transitions
- Added custom font ("stonehenge")
- Updated homepage content
- Modifed quest.js to tweak appearance of clues
- Modified generateCluesList() and addClueMarker() in quest.js to open clue as dialog rather than page