Code tidying

[magicus]

I let IntelliJ go through the code, and looked at more or less all suggestions. Those that made sense was accepted by me, sometimes with additional changes to look good in the context. I have manually verified all diffs before committing.

I have also set a consistent import order, trying to match the dominant style in the code base:

import java.*

import all others

import ru.bulldog.justmap.*