Patch #7897 Texture Nodes!

Robin (Frrr) Allen did a decent job on this, so we can also welcome him
as a member in the svn committers team to maintain it!

I do the first commit with some minor fixes:
- get Makefiles work
- fix rounding issue with tiles on unit faces
- removed UI includes from tex node

A nice doc in wiki is here:
http://wiki.blender.org/index.php/User:Frr/TexnodeManual

On the todo for Robin is:
- When using one or more Texture-input nodes, you cannot edit them by activating
  (as works now for Material nodes).
- The new "output node" option fails on the default case, when only one
  output node is active. It then shows often a blank menu. Will get fixed asap.
- When using a NodeTree-Texture as input node, the menu for 'active output'
  should not show. NodeTree should ignore other nodetrees to keep things sane
  for now.
- On a future todo is proper usage of "Dxt" and "Dyt" texture vectors for
  superior antialising of checkers/bricks.

General note; I know people are dying to get a full integrated shader system
with nodes. In theory we could merge this with Material Nodetrees... but I 
rather wait for a solid and very well thought out design proposal for this, 
also including design ideas for unifying with a shader language (GPU, CPU).
For the time being this is a nice extension of current textures. :)

source/blender/render/extern/include/RE_shader_ext.h

@@ -183,6 +183,7 @@ typedef struct ShadeInput
 /* node shaders... */
 struct Tex;
 int	multitex_ext(struct Tex *tex, float *texvec, float *dxt, float *dyt, int osatex, struct TexResult *texres);
+int	multitex_thread(struct Tex *tex, float *texvec, float *dxt, float *dyt, int osatex, struct TexResult *texres, short thread, short which_output);
 
 /* shaded view and bake */
 struct Render;