Convert the MPI_Status_f082f, MPI_Status_f082c, and MPI_Status_f2c man
pages to Markdown. Fix some typos and improve the text a bit along
the way.
Left the raw NROFF redirect pages MPI_Status_f2f08, MPI_Status_c2f08,
and MPI_Status_c2f files as they were -- they're 1-line redirects, and
it seems simpler to leave those (vs. duplicating the Markdown).
Signed-off-by: Jeff Squyres <jsquyres@cisco.com>