Feature Request: testing framework

[melithine]

There are a lot of features and combinations of configurations that exist, and trying to test everything for a new release is challenging given the small number of developers involved in the project. A good test framework that we can run when we've got a release candidate ready would really help with the overal stability of the application.

Technical notes:

• Noninteractive mode would probably need to be expanded so that we can support downloading a specific post or message non-interactively.
• The test framework itself would need it's own configuration file as to what single message / posts to use, what the expected filenames should be, etc. Also probably need to support pointing at multiple configuration files and multiple auth files, as testing content from deleted users probably needs to be done across a different account than the normal one.