message: definitively fix the Embree version required problem
diff: @@ -35,7 +35,7 @@ before you can build OSPRay you need the following prerequisites:
  system, which we recommend for performance and flexibility reasons.
  Alternatively you can set CMake variable `OSPRAY_TASKING_SYSTEM` to
  `OpenMP`, `Internal`, or `Cilk` (icc only).
  -- OSPRay also heavily uses [Embree], installing version 2.15 or newer
  +- OSPRay also heavily uses [Embree], installing version 3.1 or newer
  is required. If Embree is not found by CMake its location can be
  hinted with the variable `embree_DIR`.
  