Fix CMake warning

 - warning introduced through CMake v2.8.12-2
 - related to http://cmake.org/Bug/view.php?id=14441
Handle mpiInfo & cuda_memtest as external projects

 - projects were build as subdirectories. This now done through the
   ExternalProject module, which is available since CMake 2.8
Comment to trigger build
Fix build issues for external project
Remove External Project Again
Merge pull request #1 from ax3l/fix-cmake_warning_src

Remove External Project Again
Merge pull request #366 from slizzered/fix-cmake_warning_2-8-12

CMake: 2.8.12 Warning and External Projects