This ticket is taking over for mcous/gerber-plotter#14.

Although it should be exceedingly rare (as in, I've only seen it happen as a result of other bugs in the stack), the plotter crashes hard if it attempts to operate using a tool that isn't defined.

expected behavior

If the plotter encounters an operation using a tool that isn't defined, it should emit an error and no-op.

actual behavior

The plotter throws a TypeError that isn't catchable because it's happening in an async handler.