- extract MaterialHelper and move all of its members to aiMaterial in /include.

- pull in IOhannes' patch to set the gcc default visibility for all symbols to NO and to mark ASSIMP_API with __attribute__ ((visibility("default"))).
- drop unneeded ASSIMP_API from most internal classes in /code, we just need to keep some exports on Windows to keep AssimpView alive.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@1066 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/RawLoader.cpp

@@ -290,7 +290,7 @@ void RAWImporter::InternReadFile( const std::string& pFile,
 			}
 
 			// generate a material for the mesh
-			MaterialHelper* mat = new MaterialHelper();
+			aiMaterial* mat = new aiMaterial();
 
 			aiColor4D clr(1.0f,1.0f,1.0f,1.0f);
 			if ("%default%" == (*it2).name) // a gray default material