Repo cleanup

[ErinWeisbart]

Final few questions for cleanup of repo:

@callum-jpg We can remove the requirements.txt and requirements-windows.txt from the repo now, right?

@bethac07 We're not using Travis CI anymore so we can remove the .travis.yml, right?

@hinerm Can you clarify what is in the cpij folder? Is it necessary? Since we have moved runimagjscript.py to a new folder (active_plugins along with all other active plugins), does it need to move too?

[bethac07]

Yes, Travis can be removed; cpij is needed and should move alongside the plugin.

[callum-jpg]

Yep, anything that was contained in the requirement files will be kept in setup.py in future