[FEATURE] Use less space between siblings

[ekdahl]

Description of the desired function

Reduce unused space between branches in the tree.

Purpose of the function

Fit more actual data in the output. The screenshot shows the area I think can have reduced width (or height depending on orientation).

Concrete use cases

Being able to see the whole tree on screen or paper for a few generations.

[xiaoyang2013]

Thank you everyone, I also hope there will be such changes.