RF: whitespace cleanup and BytesIO for StringIO
RF: remove duplicate code / whitespace cleanup

Remove code already in wrappers module.
DOC: whitespace and docstring edits
RF: use relative imports from defining modules

Make clear where code comes from with specific imports. Make tests into
a package with __init__ file.
DOC: update defines docstring to standard
RF: rename argument to repeat last argument

Rename 'globbing' argument to 'last_repeat' because it seemed closer to
what I now think it means.
RF: remove yield from tests

yields make the tests difficult to debug.
DOC+RF: document wrapper classes; rename variables

Also - set shell to be always True when calling shell commands.
RF: command as tuple instead of string

Use segmented tuple as command by default, instead of concatenated
strings.
RF: python 3 compatibility