heater.c: Add comments about units of PID variables and constants.
simulator/heater_sim.c: Add notes that the heater isn't implemented in the simulator.
heater.*:Adjust DEFINE_HEATER macro to provide PID values.
config.issue74.h: M130-M136 set and report the PID values.
heater.c: Add units comments and sum the PID in consistent units, changing internal kP,kI,kD meanings.
config.teensypp.h: Add note on compiling from the command line
heater.c, heater.h, gcode_process.c: Replace hard-coded PID I_LIM with adaptive anti-windup logic.
config.issue74.h: Add 'MCU_TARGET=atmega644p  make -f Makefile-AVR' command line note.
heater.c: Add some PID units notes.
heater.*: Remove PID I-limit traces.
gcode_process.c: Add comment on units of P - M130 , I - M131, and D M132 parameters.
heater.c: Apply *16 factor to integral accumulator backcalculation (1Cs=16qCqs).
config.teensypp_drf.issue74.h: align with config for my machine.
Move the PID_SCALE_[PID] into heater.h from config.*, and apply them.
heater.*: change and doucment units for PID parameters
heater.c:Add #define BUMPLESS code for smooth transitions during adjustment of PID parameters.
heater.c:Adjust PID_SCALE_D to divide by TH_COUNT samples.
heater.*, config.teensypp.h: Switch from Ti,Td to kI, Kd.