May 20, 2018

* Map obj and sprite obj only load textures only when visible in the view.
* Util module added Good.GetScreenPos to get object screen coordinate.
* Fixed error of get color obj dim info.
* Changed to draw up to 1024 objs in a draw call.
* Added Graphics.GenCanvas and Graphics.KillCanvas to support create and destroy canvas obj.
* Added Resource.UpdateTex to update texture content from canvas.
* Added draw to canvas support to Graphics.FillRect, Graphics.DrawImage and Graphics.DrawText.