RA homing off the rails

[anjok]

When I set the speed/accel of the new stepper lib too high (I used 16.0 for both), MHRR3 doesn't find the magnet anymore and subsequently goes off the rails on the other side (which is actually a second issue as it shouldn't do so).

Issuing :RM# before the homing makes it kinda work again, but it doesn't move to 0 afterwards. Apparently the RA moves are "weird". When I give MXr100, it moves 100 steps. When I give MXr200, it just doesn't stop until I issue Q.