Improve default for homepage name.
Compute scaled icon width from scaled icon height.

This commit has no visible effect, but prepares for improving the
calculation of the new icon width and height for icons that are not
32x32 pixels.
Improve icon scaling.

Always scale to height 16 pixels. This works better if the icon is not
32x32 pixels.
Script handin generation.
Remove solution column.
Add !image (adapted from !integer).
Add missing import.

This dependency on 2htdp should be avoided. Maybe this module should
export a macro that generates macros like !image and !integer.
Share image teachpack between sandbox and checker.

The image type is generative, so we have to be careful not to get two
different image types inside and outside the sandbox.
Show images in status server.
Fix conditional.
Fix Xexpr nesting.
Fix image source. Hopefully.
Insert line break before image.