add block to stop program (#943)

* add block to stop program

* renaming

docs/reference/brick/exit-program.md

@@ -0,0 +1,18 @@
+# exit Program
+
+Stops the program and returns to the brick menu
+
+```sig
+brick.exitProgram();
+```
+
+## Example
+
+Do a sequence of motor commands and stop the program.
+
+```blocks
+motors.largeA.run(50)
+pause(500)
+motors.stopAll()
+brick.exitProgram();
+```