Make scaling optional/configurable

[JohnnyMoonlight]

Hello,

thank you for your software and the work you put into it.

I have a use case, in which I would like to prevent users to change the scaling. They only want to download the map excerpt. For this, there might be two possible solutions:

1. Check for equality of the options minScale and maxScale. If they are equal, the function call for _createScaleInput() could be omitted.
2. Add parameter-object, in which the scale is configured. If object is empty, the scale-rendering calls are omitted.

I am lookin forward to your feedback!

Best regards