SANS2D Front Beam Stop inhibit movement

A requirement of ticket #4581 was to inhibit motion in the front beam stop if the detector rotation is greater than 0 degrees (later it was discovered that SECI allowed motion of the beam stop when -2 < detector rotation < 2). This works by processing a record every time the rotation or it's setpoint changes and if either is less than -2 or greater than 2 then it sends a stop to the motor and sets a DISP on the axis and its setpoint. In the team, we discussed setting a DISP on the motor record, but seeing as we are constantly stopping a drive towards a setpoint by actively sending a stop to the motor this doesn't seem necessary. We are also wary of setting a DISP on the motor record because it prevents the use of the stop button on the motor record.