Added test coverage
Added requirements.txt for pysftp
Added in the roadmap the exact version of pysftp for this to work (0.2.8)
Added in the roadmap the problem with list_db=False
Adapted calls to message_post
Used to open fp = open(file_path,'wb') a few lines before it was needed. This shouldn't be too much of a problem but opening and closing it right after eachother keeps the session open for less time and there are less chances on failure.