When running ffcx on a file foo.py file, the 'namespace' used in generated code is taken from the file name, i.e. foo.

This means that code generated from foo.py using different options, e.g. different scalar types, cannot be used in a program at the same time.

Proposal is to

• Add a command line option to set the 'namespace', i.e. replace foo with a user-controlled name. Default behaviour would be as it is now.
• Add a command line option to set the names of the generated files.

Another issue slightly related issue: command line options -o fails if the target directory does not exists.