Handle CANCEL touch events

Handling this event is part of the API but was never done. This caused
unstoppable key-repeat.

This event isn't common, the only way I found on Android 10 is to switch
to the emoji keyboard while holding a key. Some apps might cause this
event more often.

srcs/juloo.keyboard2/Keyboard2View.java

@@ -129,6 +129,9 @@ public class Keyboard2View extends View
         for (p = 0; p < event.getPointerCount(); p++)
           _pointers.onTouchMove(event.getX(p), event.getY(p), event.getPointerId(p));
         break;
+      case MotionEvent.ACTION_CANCEL:
+        _pointers.onTouchCancel(event.getPointerId(event.getActionIndex()));
+        break;
       default:
         return (false);
     }

srcs/juloo.keyboard2/Pointers.java

@@ -95,6 +95,16 @@ public final class Pointers implements Handler.Callback
     }
   }
 
+  public void onTouchCancel(int pointerId)
+  {
+    Pointer ptr = getPtr(pointerId);
+    if (ptr == null)
+      return;
+    stopKeyRepeat(ptr);
+    removePtr(ptr);
+    _handler.onPointerFlagsChanged();
+  }
+
   public void onTouchDown(float x, float y, int pointerId, KeyboardData.Key key)
   {
     KeyValue value = key.key0;