Print LLVM version info like this:

Print LLVM version info like this:

Low Level Virtual Machine (http://llvm.org/):
  llvm version 1.8cvs
  DEBUG build with assertions.

instead of like this:

Low Level Virtual Machine (llvm) 1.8cvs (see http://llvm.org/) ASSERTIONS ENABLED

Also, add a place for vendor version info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29020 91177308-0d34-0410-b5e6-96231b3b80d8