The code in ccutil/hashfn.h was needed for some old compilers. Now that we support MSVC >= 2010 and compilers that has good support for C++11, we can drop this code.

As a result of this file removal, we now use:
  std::unordered_map
  std::unordered_set
  std::unique_ptr
directly in the codebase with '#include' for the needed headers.