CMake: Provide a separate main.cpp for each test

Another option would have been to provide a single main.cpp.in,
and let CMake configure it during the build.
Remove the old Makefile-based build system

The old Makefiles are being replaced by a CMake build. Some features
such as MIC are not supported yet by CMake, but should be added before
being merged.
CMake: A convenience Makefile
CMake: A silly hack to show all headers in QtCreator
Revert "CMake: Don't warn about variable size arrays"

This reverts commit 24c0394196b01b37ba30d52bbbe8cadf9f6a33cf.
REBASEME: Silly hack