Minor serializer changes

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Updates
Port across minor changes -
- Header guard ifdefs

-	if (self = [super init])
+	if ((self = [super init]))

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Import GraniteDS classes.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Add callbacks rather than selectors to GDS.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>