stop all motors when pressing escape

libs/core/buttons.ts

@@ -165,8 +165,10 @@ namespace brick {
         }
         // this needs to be done in query(), which is run without the main JS execution mutex
         // otherwise, while(true){} will lock the device
-        if (ret & DAL.BUTTON_ID_ESCAPE)
+        if (ret & DAL.BUTTON_ID_ESCAPE) {
+            motors.stopAllMotors();
             control.reset()
+        }
         return ret
     }
 
@@ -190,7 +192,7 @@ namespace brick {
             initBtns()
             buttons.push(this)
         }
-    }
+    }    
 
     initBtns() // always ON as it handles ESCAPE button
 
@@ -231,6 +233,7 @@ namespace control {
     /**
      * Determine the version of system software currently running.
      */
+    //%
     export function deviceFirmwareVersion(): string {
         let buf = output.createBuffer(6)
         brick.internal.getBtnsMM().read(buf)