This is a native Meiko CS2 version of the ADI.  It is NOT derived from
the Chameleon code, though it is important to keep mpid.h and
dmmeiko.h up-to-date.

This version operates on a single tport, and packs the
source,tag,context all into the tport's tag field. (Giving them 8,16,8
bits respectively). 

It does not yet provide collective operations, which are still done by
the default code, built on top of MPI point to point operations.

