Update Reference.pdf files.

This updates the Reference.pdf files to say LLVM OpenMP Runtime Library and
also updates the build documentation to show how to build with CMake.

llvm-svn: 248407
diff --git a/openmp/www/Reference.pdf b/openmp/www/Reference.pdf
index d6faf7e..e97c40c 100644
--- a/openmp/www/Reference.pdf
+++ b/openmp/www/Reference.pdf
Binary files differ