Add mousemoved callback.

Author: rm-code

Screen.lua

@@ -61,6 +61,8 @@ function Screen.new()
 
     function self:mousefocus(focus) end
 
+    function self:mousemoved(x, y, dx, dy) end
+
     function self:quit(dquit) end
 
     function self:isActive()

ScreenManager.lua

@@ -234,6 +234,17 @@ function ScreenManager.mousefocus(focus)
     ScreenManager.peek():mousefocus(focus);
 end
 
+---
+-- Callback function triggered when the mouse is moved.
+-- @param x - Mouse x position.
+-- @param y - Mouse y position.
+-- @param dx - The amount moved along the x-axis since the last time love.mousemoved was called.
+-- @param dy - The amount moved along the y-axis since the last time love.mousemoved was called.
+--
+function ScreenManager.mousemoved(x, y, dx, dy)
+    ScreenManager.peek():mousemoved(x, y, dx, dy);
+end
+
 ---
 -- Reroute the quit callback to the currently active screen.
 -- @param dquit