Import ANSI C cityhash.

The implementation is the ANSI C adaptation (by Alexander Nusov)
of Google's original C++ implementation.

The whole is covered by an MIT-style license.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>

Conflicts:
	src/support/CMakeLists.txt
Cleanup nfsv4 file handle.
Added pseudofs hashtable