ResourceManager: privately inherit Implementation::ResourceManagerData.
ResourceManager: privately inherit Implementation::ResourceManagerData.

Protected inheritance has no sense, as there shouldn't be any subclasses
touching internals in Implementation namespace.

DerThorsten/magnum,ashimidashajia/magnum,MiUishadow/magnum,MiUishadow/magnum,DerThorsten/magnum,ashimidashajia/magnum,ashimidashajia/magnum,ashimidashajia/magnum,MiUishadow/magnum,ashimidashajia/magnum,DerThorsten/magnum,DerThorsten/magnum,DerThorsten/magnum,MiUishadow/magnum,MiUishadow/magnum,MiUishadow/magnum