change supportedrates config setting to the actual MBit value

supportedrates is now a list instead on an array and float values
(e.g. 5.5) are permited.

conf/wtp.conf

@@ -106,9 +106,9 @@ application: {
 				numberchannels = 11;
 				maxtxpower = 100; 
 			};
-			supportedrates = [
-				12, 18, 24, 36, 48, 72, 96, 108
-			];
+			supportedrates = (
+				6, 9, 12, 18, 24, 36, 48, 54
+			);
 			txpower = {
 				current = 100;
 				supported = [ 100 ];