xyst

Enable multiple meshes during mesh partitioning

Appears to work in parallel, with virtualization, employing different
virtualization for different meshes. Using different partitioners for
different meshes not yet hooked up.

Details:

* Add default partitioner (rcb) to multiple meshes.

* The user can now specify multiple virtualization arguments (by
  repeatedly specifying -u) for multiple meshes (by repeatedly
  specifying -i) on the command line.

* Screen output after partitioning is now more aware of multiple meshes.

* Removed attempting separately measure mesh distribution time, because
  starting measuring it can overlap for multiple meshes and can lead
  error and fixing it (and maintaining it) is not worthwhile.