Discard AA lines

Tested with DOA , Echochrome and Summon Night 5 , all look good .

![screen00034](https://f.cloud.github.com/assets/3000282/1050323/d365ec0a-10b7-11e3-93af-7a24f6dc3a68.jpg)
![screen00033](https://f.cloud.github.com/assets/3000282/1050325/d699f7cc-10b7-11e3-9c22-c5e296fcb125.jpg)
![screen00032](https://f.cloud.github.com/assets/3000282/1050327/d90d716e-10b7-11e3-8cce-206b05a4087b.jpg)