major speedup, refactor, and new features

[iceboundflame]

Thanks so much for this tool! It's a really great idea and CNC routed projects really aren't practical without it. I made some enhancements so that it would work for more complex models with many dogbones (my model has 208).

I know this is quite a large PR but I was having a hard time developing without first doing some refactoring first to cut down on repetition. Here's a list of changes...

Significantly optimized as follows:

• Instead of generating one plane, sketch, and sweep cut for each dogbone, it groups the dogbones by their vertical extents and produces the minimum number of features in the history tree as possible.
• Introduced "Output Unconstrained Geometry" option to directly compute the locations of dogbone circle in the sketch, producing the minimum amount of sketch geometry possible. This led to a >5x speedup of generating each dogbone.

The net result is that, for my use case, I can generate 208 fillets in 28 objects in 73 sec. Since they are all lying in the same plane, it only generates three history operations (plane, sketch, extrusion). Previously this would take forever, freeze the UI, and generate 600+ operations in the history.

Note: The bulk of the time is because every call to the Fusion API (adding geometry, extrusions, etc.) is extremely slow.

Additionally, other enhancements were added:

• Progress bar shows current status.
• The operation can be canceled midway (use Undo to delete the partial geometry created).
• Saves the last parameters used (cleared on relaunch of Fusion)
• Skips non-vertical edges selected.
• Benchmarking
• Code is refactored into object-oriented fashion to be more manageable, and utility functions split out.
• Robustness: Exception handling is consolidated, tracebacks always shown, launching the plugin automatically cleans up old crashed instances of the plugin.

[iceboundflame]

By the way, I see in the history that you used to use extrude cut as well, but switched to loft cut. I moved to extrude again in my version because I found it simpler, but I'm curious if you saw a benefit from the lofts?