Change NXmx sensor_material and sensor_thickness to required

applications/NXmx.nxdl.xml

@@ -128,7 +128,7 @@
 
 					The axis on which the sample position depends may be stored
 					anywhere, but is normally stored in the NXtransformations
-					NXtransformations group within the NXsample group.
+					group within the NXsample group.
 
 					If there is no goniometer, e.g. with a jet, depends_on
 					should be set to "."				
@@ -610,7 +610,7 @@
 						</doc>
 					</field>
 
-					<field name="sensor_material" type="NX_CHAR" recommended="true">
+					<field name="sensor_material" type="NX_CHAR" minOccurs="1">
 						<doc>
 						At times, radiation is not directly sensed by the detector.
 						Rather, the detector might sense the output from some
@@ -620,7 +620,7 @@
 					</field>
 
 					<field name="sensor_thickness" type="NX_FLOAT" units="NX_LENGTH"
-						minOccurs="0">
+						minOccurs="1">
 						<doc>
 						At times, radiation is not directly sensed by the detector.
 						Rather, the detector might sense the output from some