splits m:b simulator state

sim/state/compass.ts

@@ -0,0 +1,22 @@
+namespace pxsim.input {
+    export function compassHeading(): number {
+        let b = board().compassState;
+        if (!b.usesHeading) {
+            b.usesHeading = true;
+            runtime.queueDisplayUpdate();
+        }
+        return b.heading;
+    }
+
+    export function magneticForce(): number {
+        // TODO
+        return 0;
+    }
+}
+
+namespace pxsim {
+    export class CompassState {
+        usesHeading = false;
+        heading = 90;
+    }
+}