Accumulate (slideX, slideY) with touch slide events.

Apparently, onTouchSlide gets called more frequently, and hence we miss some of the sliding if we do not accumulate between calls to Lua.

radio/src/lua/widgets.cpp

@@ -482,6 +482,8 @@ void LuaWidget::refresh(BitmapBuffer* dc)
         if (swiped)
           swipeTimeOut = get_tmr10ms() + EVT_TOUCH_SWIPE_TIMEOUT;
       }
+      slideX = 0;
+      slideY = 0;
     }
   } else
 #endif
@@ -584,8 +586,8 @@ bool LuaWidget::onTouchSlide(coord_t x, coord_t y, coord_t startX, coord_t start
     touchY = y;
     LuaWidget::startX = startX;
     LuaWidget::startY = startY;
-    LuaWidget::slideX = slideX;
-    LuaWidget::slideY = slideY;
+    LuaWidget::slideX += slideX;
+    LuaWidget::slideY += slideY;
     lastTouchDown = 0;
     
     return true;