ResourceManager: assertions on global instance pointer.
ResourceManager: assertions on global instance pointer.

Better be sure than crash somewhere deep in STL code.

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