message: Fix include paths for tests
diff: # This file is distributed under the MIT license.
  # See the LICENSE file for details.
  +# Visionaray include dir
  include_directories(${PROJECT_SOURCE_DIR}/include)
  +# Also add this so we can include common headers
  +include_directories(${PROJECT_SOURCE_DIR}/src)
  +# Find config headers
  +include_directories(${__VSNRAY_CONFIG_DIR})
  add_subdirectory(algo)
  add_subdirectory(packing)
  