add documentation about kerberos auditing
Merge pull request #633 from kholia/kerberos-auditing

add documentation about kerberos auditing
Removed last traces of mmx MMX_COEF code.  This was causing serious problems in dynamic, and other formats. Even things were having probems building. NOW, DES/BF, etc still use MMX, but all MD[45], SHA1 do not
Renamed Makefile.orig to Makefile.legacy.  The .orig was a BAD idea, as this was a special extension and prone to be overwritten and lost
Made a little more robust.  Had some old projects with HAVE_REXGEN defined.  By adding this simple logic, it will work either with HAVE_REXGEN or HAVE_LIBREXGEN being defined. It will still unset the logic IF the lib is found and too old