Robot: 82dae6 introduced a bug where the first segment junction would needlessly decelerate to zero speed. Turns out, we don't need these conditions
Endstop: don't report name during startup
Homer: check that required endstop exists, adjust list if not
main: add Endstops module to kernel
Robot: accept lines with null gcode, make append_line and append_actuator_milestone public for use by other modules
Homer: more fleshing out of homing process, still incomplete. WARNING: may cause lockup on G28 since we don't actually move yet
Homer: call ON_IDLE event while homing