Update fc64x8 CAD files with final design from Adafruit

- Remove outdated BOM file (Adafruit doesn't use a separate BOM spreadsheet)
- Added fiducials
- Added Adafruit logo
Python 3 compatibility
Style cleanup
Variant of grid32x16z_particle_fft using line input
OPC-style JSON layout files for some example LED grids
Particle trail example for Node.js

Shows easy and high quality particle animation with JavaScript
Update README.md
New diagrams

Details of how fcserver and the controller operate
Adding testjig PCB contributed by Ryan O'Hara
Mention CAD packages in README
Make loadModel() a static method
Add a triangle FFT visualizer tweaked for mic input
HSV color for opc.js
New particle system example in Node.js
Switch flat grid layouts to use XZ plane

Now things look good with the default camera in gl_server
Experimental complex layout for a 6x12 window display
Gracefully handle unmapped LEDs in opc.js
Handle negative hue values in hsv()
Include simplex-noise module in the node.js examples

Super useful!
Node.js version of the "rings" effect