Option to emit mildly optimized svg paths

[rsheeter]

To enable deletion of some java code and a somewhat slow step in icon svg processing provide an optional optimized svg path that does the following if/when it produces a shorter string:

• [x] Use relative vs absolute coords
• [ ] Collapse repeated lines (e.g. h20 h30 -> h50)
• [x] Use lineto shorthands (e.g. horizontal or vertical line)
• [x] Remove nop instructions, e.g. l0,0 but more generally any command that doesn't move the pen
• [x] Decrease accuracy of floats
• [ ] Convert degenerate curves to lines
• [ ] Drop leading 0 when possible (e.g 0.5 => .5)
• [x] Drop separator between coords when second is negative, e.g. emit 160-160 not 160,-160
• [x] Use "smooth" cubic/quadratic curve commands when possible (reflection of end of previous gives first control)

That is, implement most optimizations from https://github.com/svg/svgo/blob/main/plugins/convertPathData.js but apply during generation of a String for a BezPath instead of as a standalone step. Consider not implementing arc conversion; arcs have a way of breaking things.

Impact: should cut minutes off the time to produce a complete set of icons.

See:

• https://www.w3.org/TR/SVG11/paths.html#PathData
• https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/d#path_commands
• https://svgo.dev/docs/preset-default/#plugins-list
  • Note that as we generate the svg many remove element steps are avoided by simply not generating them

[tomasdev]

Collapse Repeated from SVGO https://github.com/svg/svgo/blob/main/plugins/convertPathData.js#L748-L767