Modelling SHMEM in Ember

[deanchester]

The ember documentation primarily focusses on MPI motifs. Cornelis has recently done a lot of work to get the SHMEM motifs in a stable condition and would like to document how some of the internals work as they are different to to how MPI motifs are developed.

This will require some minor changes to the existing Ember documentation so that pages are more descriptive about being for MPI or SHMEM.

Comments welcome.

[gvoskuilen]

This would be great!