PositionDeadband, dynamic limit detection, velocity mode

Integrated a readout function for the position deadband. Also read from
the controller if the axis has dynamic limits and only poll the limits
repeatedly if that is the case. Lastly, added support for the velocity
mode (untested!).

src/masterMacsController.h

@@ -54,6 +54,15 @@ class HIDDEN masterMacsController : public sinqController {
      */
     asynStatus readInt32(asynUser *pasynUser, epicsInt32 *value);
 
+    /**
+     * @brief Overloaded version of the sinqController version
+     *
+     * @param pasynUser
+     * @param value
+     * @return asynStatus
+     */
+    asynStatus writeInt32(asynUser *pasynUser, epicsInt32 *value);
+
     /**
      * @brief Get the axis object
      *