Fix ultrasonic value to use cm instead of 0.1 cm units (#110)

* Fix simulator

* use 250 instead of 255

sim/state/util.ts

@@ -1,7 +1,7 @@
 namespace pxsim.util {
 
     export function map16Bit(buffer: Uint8Array, index: number, value: number) {
-        buffer[index] = (value >> 8) & 0xff;
-        buffer[index+1] = value & 0xff;
+        buffer[index] = value & 0xFF;
+        buffer[index + 1] = (value >> 8) & 0xFF;
     }
 }