Modified Rendering Code

Purpose:
- Trapezoids textures no longer sheer a long the triangle edges. 
   sheering: http://i.imgur.com/0cVU9CT.png
   fixed: http://i.imgur.com/P5nLe5q.png

Additions:
- TmtTesselator.java: Vanilla Tessellator modified to expose the OpenGL
  Q texture coordinate
- PositionTextureVertex.java: Vanilla PositionTextureVertex extension
  modified to allow the Q coordinate to be stored with the vertex, removes
  requirement for a base class modification

Changes:
- ModelPoolEntryObj.java: Utilizes the new PositionTextureVertex object
- ModelRendererTurbo.java: Adds Q coordinate calculations to trapezoids
  (other non-rectangular shapes can be done later), adds Q coordinates to
  the PositionTextureVertex's created by the addPolygonReturn function
- PositionTransformVertex.java: Utilizes the new PositionTextureVertex
  object
- TextureGroup.java: Replaced TexturedQuad with TexturedPolygon in order
  to remove requirement for a base class modification
- TexturedPolygon.java: No longer extends TexturedQuad to remove
  requirement for a base class modification, utilizes the new
  PositionTextureVertex object, utilizes the new TmtTessellator for
  rendering

Hopefully this code will fit with the current style (tabs not spaces, etc.) If you find a bug, I will try to recreate it and debug it. Also I plan on adding the Q coordinates to some other non-rectangular shapes