Recursive process

[jedbakerMO]

Description

Adds an optional parser argument to run the script recursively, looking through subdirectories to process mutliple tests at once.

If the optional recursive argument is used then all subdirectories are searched and valid ones are added to a list which is then looped through when processing. If not used, the only directory added to the loop list is the one given.

Linked issues

Closes #207

Type of change

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• New tests have been added
• Tests have been modified to accommodate this change
  I have manually tested this with outputs to confirm they are being processed properly.

Checklist:

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes, for both debug and optimised builds

[jedbakerMO]

Many changes are formatting here and general tidying here, particularly in the argument parser areas.