Added MAGNUM_*_INCLUDE_DIRS for all modules too.
Added MAGNUM_*_INCLUDE_DIRS for all modules too.

Some modules need it (Sdl2Context), some not.

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