Fix texture coordinates for Plane primitive

The texture coordinates for the plane was rotated by default causing PostProcessingRenderer to display the framebuffer texture incorrectly. Also, other general textures on the plane would appear rotated. This is a simple fix that corrects the texture coordinates.

#### BEFORE FIX
![Screenshot_2013-04-21-16-28-30](https://f.cloud.github.com/assets/3170805/406153/abd3f6be-aa64-11e2-8aee-7cd853fff86a.png)

#### AFTER FIX
![Screenshot_2013-04-21-18-20-48](https://f.cloud.github.com/assets/3170805/406154/dcd1a5f4-aa64-11e2-87c7-f858a8c0ef5b.png)