add block to stop program (#943)

* add block to stop program

* renaming

libs/ev3/brick.ts

@@ -0,0 +1,13 @@
+namespace brick {
+    /**
+     * Exits the program to the main menu. (in the simulator restarts it)
+     */
+    //% blockId=loopstop block="exit program"
+    //% help=reference/brick/exit-program
+    //% weight=10
+    //% blockGap=8
+    //% group="Buttons"
+    export function exitProgram() {
+        control.reset();
+    }
+}

libs/ev3/ns.ts

@@ -1,6 +1,6 @@
 
 //% color="#68C3E2" weight=100 icon="\uf106"
-//% groups='["Buttons", "Screen", "Battery"]'
+//% groups='["Buttons", "Screen", "Power"]'
 //% labelLineWidth=60
 namespace brick {
 }

libs/ev3/pxt.json

@@ -2,8 +2,9 @@
     "name": "ev3",
     "description": "The EV3 library",
     "files": [
-        "README.md",
+        "README.md",        
         "ns.ts",
+        "brick.ts",
         "startup.ts",
         "images.jres",
         "images.ts",