Various minor changes to tutorial scripts. In particular, ensuring that
they all change to the containing directory so that batches of tutorials
can be run easily from the root of the installation.
This tutorial serves as an example of a boiling transfer between two
phases, which occurs on the surface of a third stationary phase. See
commit 32edc48d for details of this modelling and its specification.
Patch contributed by Juho Peltola, VTT.
