Pins gestures grid (#400)

* Change pins and gestures to use grids

* Use grid picker for pins and gestures

libs/core/input.cpp

@@ -134,6 +134,7 @@ namespace input {
     //% help=input/on-gesture weight=84 blockGap=8
     //% blockId=device_gesture_event block="on |%NAME"
     //% parts="accelerometer"
+    //% NAME.fieldEditor="gridpicker" NAME.fieldOptions.columns=4
     void onGesture(Gesture gesture, Action body) {
         int gi = (int)gesture;
         if (gi == MICROBIT_ACCELEROMETER_EVT_3G && uBit.accelerometer.getRange() < 3)