- for protocol version >= 27, mdfour_tail() is called when the block size

   (including checksum_seed) is a multiple of 64.  Previously it was not
   called, giving the wrong MD4 checksum.

 - for protocol version >= 27, a 64 bit bit counter is used in mdfour.c as
   required by the RFC.  Previously only a 32 bit bit counter was used,
   causing incorrect MD4 file checksums for file sizes >= 512MB - 4.
						-- Craig Barratt