metomi/rose#27: rose mpi-launch -v.

--debug: switch on xtrace.
-v: print command.
-v -v: printenv, ldd, ulimit -a.
Merge branch 'master' into 27.rose-mpi-launch.v
rose mpi-launch: use site/user config.

Previously hard coded settings, e.g. list of default launchers, their
pre-opts and post-opts are now configurable in the site/user
configuration.

Support for ROSE_LAUNCHER_MPICH removed.
Merge branch 'master' into 27.rose-mpi-launch.v
Merge branch 'master' into 27.rose-mpi-launch.v
Merge branch 'master' into 27.rose-mpi-launch.v
metomi/rose#316: fail-if page
Merge branch 'master' into 27.rose-mpi-launch.v

Conflicts:
	lib/python/rose/config_cli.py
Merge branch 'master' into 27.rose-mpi-launch.v

Conflicts:
	lib/python/rose/config_cli.py
Merge branch 'master' into 27.rose-mpi-launch.v
training: fail-if tutorial
metomi/rose#316: tidy
Merge branch 'master' into 27.rose-mpi-launch.v
metomi/rose#316: fix
metomi/rose#316: tidy
metomi/rose#316: better name
metomi/rose#316: add all explanation
metomi/rose#316: outline
Merge branch 'master' into 27.rose-mpi-launch.v
metomi/rose#316: finish content