motionblur: use anonymous typed enum instead of static const member.
motionblur: use anonymous typed enum instead of static const member.

One exported symbol less.

mosra/magnum-examples,Squareys/magnum-examples,Squareys/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,Squareys/magnum-examples,Squareys/magnum-examples,mosra/magnum-examples,mosra/magnum-examples