Display 1 degree as number, not text

There are two types of labels: One half ranges from `±0.000001°` to `±10°`. The other half is based on minutes and seconds and shown as text.

But why is `±0.1°` a number, `±1°` is not a number but `±10°` is a number again? Discussed with @lydiapintscher and decided to remove it. It's not translated anyway.

Note: This is related to https://github.com/wmde/ValueView/issues/60 but can be merged independently. May need a new version number, though.