After making boost a core dependency some nightlies have two failing diffusion tests.

This is due to the tests being build and executed as the DiffusionCore dependencies are met, but DiffusionIO's are not (Vigra/HDF5 via FiberTracking) and thus the tests try to load images for which no readers have been registered.

The proper way to fix this would be to refactor the diffusion modules to use the suggested module layout [1]. That way all tests/readers/cmdapps will be located in the appropriate module and be available.

This should be relatively straightforward.

[1] http://docs.mitk.org/nightly/NewModulePage.html