Mobile display issues on various page types

[FayCross]

The following pages could have their mobile/small screen display improved:

• [x] Hotspot Image: image should be 100% width
• [x] Drag & drop labelling: image should be 100% width
• [x] Hotspot Question: image should be 100% width
• [x] Wordsearch: puzzle can be too wide for screen
• [x] YouTube Video: iframe can be too wide for screen