Merge branch 'bug-210-separate-test-images'

• bug-210-separate-test-images: Added MITK-Data as a dependency to MITK-Utilities. Make standard module tests use MITK_DATA_DIR path Use anonymous http clone for MITK testing data Make MITK_DATA_DIR available for external projects via MITKConfig.cmake Pass MITK_DATA_DIR in superbuild New external project MITKData that checks out the testing data repository