include headers in cmake source, added a script to check for consistency, reporting missing headers & C files.

this is important so IDE's using CMake integration always get blender headers. - QtCreator & MSVC for eg, probably others too.

source/blender/editors/interface/CMakeLists.txt

@@ -50,6 +50,8 @@ SET(SRC
 	resources.c
 	view2d.c
 	view2d_ops.c
+
+	interface_intern.h
 )
 
 IF(WITH_INTERNATIONAL)