Use MSG_NOSIGNAL when sending to receivers to prevent SIGPIPE.
Removed debug noise.
Removed definitions of LOW and HIGH.  They are defined in back/pin-io.h.
Cosmetic.  Now define air pump before water pump.
Removed extraneous inclusion of <stdbool.h>.
Added an XXX comment that code to read SPI bus is unnecessary.
Declared current_animation() to see what's playing.  Did not implement it.
Now prints "Ready" on startup.  Better serial error handling.
Cosmetic.
Lots of clarification and rewording.
Debugged parser.  Implemented lots of simple actions.
Now the firmware prints a version string on startup.