A last few changes before 4.1.
The first figure in "Using Companion app" needs a third part.
This was inserted. Which, in turn, affected the last figure
in that section. So that was also changed accordingly.
Few tiny changes to text to clean up references to figures.
Signed-off-by: Willem Ferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
