Circle and text size

[evansmj]

Stakeholder says:

"I would like to see the text of the node name bigger, and the circle smaller."

The node name text can be long in regtest at least, and maybe other situations.

I thought i had the text resizing to fit in the circle. If its not, then that should be the way to fix it.

Maybe we can have an options menu where the user sees 2 sliders, one for circle size and another for text size? But a redraw of the graph would need to happen when a value is changed.