viewer: make it possible to override the importer.
viewer: make it possible to override the importer.

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