Added getMeasurementDataCoding to helper lib that
                    returns the datacoding byte for measurement classes
                    that have it. Use the VSCP_DATACODING_TYPE, VSCP_DATACODING_INDEX
                    and VSCP_DATACODING_UNIT macros to get individual parts in it.
                  Added new action parameter escapes
                    %measurement.index  - index for sensor (0-7)
                    %measurement.unit   - measurement unit (0-3)
                    %measurement.coding - datacoding       (0-7)
                    %measurement.convert.data - which convert all types
                        of measurement data into a VSCP_CLASS2_MEASUREMENT_STR
                        data coding which can be easier to directly interpret
                        without code.