o Not using isolators for now.
o remove reference to isolators lib.
o Add analog inputs with input protection.
o add input protection to end switches.
o Add LDO to create a local 3.3V from 5V; use that everywhere, don't
  use 3.3V provided by BBB
o Add LEDs to heater PWM.
o Remove footprint overlay for new components.
o Update schematic image.