An interface to allow for mocking out "io" package reading-related methods.

------------------------------------------------- A console where things can be written to so the user can see them.

Environment is a thin interface layer above the os package which can be mocked out.

We use the factory to create instances of various classes.

FileSystem is a thin interface layer above the os package which can be mocked out.

A final word handler can set the exit code of the entire process.

A class which houses both the cobra command and the values structure the command puts things into.