Add a setting property to the beamline C154 to reflect the position setting
Wally Kissel has requested a new setting property in the C154 driver to reflect the current position that was set. The current setting is non-intuitive; you set the property to 1 or -1 to move the device but the reading of the setting returns the CAMAC module's internal counter which counts down at 150Hz and is essentially always zero.
For this modification, a new setting property will be added which reads the limit switch status to determine what the setting was. Wally will use database enumerations to give the values useful descriptive text.