motors moving: extend in-motion to bit mask

Current the motor util library provides an "in motion" flag for the IOC as a whole, this is too generic as if one motor is constantly moving the whole IOC says "in motion" and cannot be part of a ususal "wait for move". If motorUtils provided a bit mask (one bit per motor) then it would be easier to exclude just one motor from the calculation. The alternative is to change to monitoring DMOV on all individual motors of interest rather than using motorUtil