[PATCH] Added doxygen support for the tools of clang-tools-extra repo

[Ariel Bernal]

  Silvas: do you mean removing footer, header styles and intro and adding the intro to the index file, leaving only the Doxyfile, is that right?. I have no problem using the default doxygen style.
  Regarding the CMake support, I think is a broader change since there is no CMake support for llvm/clang documentation now, but it can be added as well, maybe in a different patch. What do you think?

http://llvm-reviews.chandlerc.com/D451