Zoom and van tracking

[lauracumming]

Describe the bug The tracking of the character in levels with large maps does not really work properly. It gets worse the more the player zooms in.

To Reproduce Steps to reproduce the behaviour:

1. Go to level 78.
2. Solve the level (ask the CfL team for the solution).
3. Click Play.
4. Observe the character tracking feature, where the map is moved to ensure the character stays visible.
5. Close the success popup, stay on this level.
6. Zoom in a bunch.
7. Press play again.
8. Observe that this time, the tracking feature fails to keep the character in view.

Expected behaviour No matter how much the map is zoomed in, the character should always be tracked and visible on the screen.

[lauracumming]

We also need to move the buttons to fit the UI area for tablets

[lauracumming]

This is dependent on another task which looks at the view window.