Add Delete operator to modal header
Update wording for Adjust Segments in modal header
Update theme structure in preparation for updated theme colors
Update theme label in prefernces.
Add new theme color presets and rework theme assignment a bit.
Prettify Polystrip handles!

This smoothes the drawn points, resulting in nicer handle drawing that better matches Pawel's original design.
Update visualization style to more closely match Contours.
Increase smoothing amount on sketch lines to 0.75.
Rework theme colors a bit more, further matching Contours.

Now Polystrips and Contours theme system almost matches exactly, and wil be easy to extend a bit more when we have multi-selection support.
Update color of sketch lines.
Update amount of smoothing for each Smooth Tool operation
Make mesh lines thinner to be less distracting.
Update readme.
Remove beta warning. Close #42
set sel_gedge in PolystripsUI
Fix merge conflicts