[bdbarnett]

Closes #145.

A NaN passed for a numeric constructor option reached _build as it was, so 32 effect classes rendered something that was neither the default nor zero. The base Component constructor now drops a NaN option (keyword, or positional where the interpreter can name the arguments) before _build runs, so the option takes its default as each class's documentation says. One rule covers every class.

Four options keep the NaN meaning their class already documents and tests: Glide on DigitalDelay and TapeDelay (the jump), damping on ConvolutionReverb (out of circuit) and interval on ShimmerHall (refused). A class names such an option in _NAN_OWN.

CabinetSim.set_macro snaps a float to the nearest of 128 positions on purpose. A constructor option off the grid is not on that grid, so echoing get_macro() back moved it (46.99 read back as 47). The number get_macro() itself returned is now kept; any other float still snaps. SlapbackDelay already echoes exactly on current main, and the new test holds it there.

Tests: tests/test_nan_options.py renders every effect with each numeric option set to NaN against the option left out, checks the get/set round trip and the audio on both classes, and checks that a chosen float still snaps.