Cycles OSL: shader script node

Documentation here:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/OSL
http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.65/Cycles

These changes require an OSL build from this repository:
https://github.com/DingTo/OpenShadingLanguage

The lib/ OSL has not been updated yet, so you might want to keep OSL disabled
until that is done.

Still todo:
* Auto update for external .osl files not working currently, press update manually
* Node could indicate better when a refresh is needed
* Attributes like UV or generated coordinates may be missing when requested from
  an OSL shader, need a way to request them to be loaded by cycles
* Expose string, enum and other non-socket parameters
* Scons build support

Thanks to Thomas, Lukas and Dalai for the implementation.

intern/cycles/render/nodes.h

@@ -445,6 +445,18 @@ public:
 	SHADER_NODE_CLASS(SetNormalNode)
 };
 
+class OSLScriptNode : public ShaderNode {
+public:
+	SHADER_NODE_CLASS(OSLScriptNode)
+	string filepath;
+	string bytecode_hash;
+	
+	/* ShaderInput/ShaderOutput only stores a shallow string copy (const char *)!
+	 * The actual socket names have to be stored externally to avoid memory errors. */
+	vector<ustring> input_names;
+	vector<ustring> output_names;
+};
+
 CCL_NAMESPACE_END
 
 #endif /* __NODES_H__ */