Fix regression in salt-call

This fixes a regression that I inadvertently caused in d749e5a by
always wrapping the return data in a dict. An extra step here in the
Caller class was duplicating this action, causing a traceback when
attempting to increment the result counts for the highstate outputter.
add docker
Added docstrings, examples, virtual method
docker: complete create_container
docker: complete export
pep8 pass