cms-dev
Add the shell programming language
See title. This fixes running cmsMake with bash scripts as generators.
This change is 
Could you update the documentation and possibly add some tests? See #731 for an example.
I would advise against using /bin/sh as the shell to execute as it may be a different shell on different systems. I think the decision on what to do with /bin/sh is up to the single OSes or Linux distros.
On Debian and Ubuntu /bin/sh is a symbolic link to dash, but previously it was bash. On Mac OS X it's bash (precisely bash v. 3.X, which is the default that ships with OS X).
It would be better using a more specific shell and also indicate the version, as for example Bash 4.0 introduced support for associative arrays.
