- 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/MDLFileData.h

@@ -763,7 +763,7 @@ struct IntMaterial_MDL7
 	}
 
 	//! Material instance
-	MaterialHelper* pcMat;
+	aiMaterial* pcMat;
 
 	//! Old material indices
 	unsigned int iOldMatIndices[2];
@@ -909,7 +909,7 @@ struct IntSharedData_MDL7
 	std::vector<bool> abNeedMaterials;
 
 	//! List of all materials
-	std::vector<MaterialHelper*> pcMats;
+	std::vector<aiMaterial*> pcMats;
 
 	//! List of all bones
 	IntBone_MDL7** apcOutBones;