Added restore media for rsync backup. Bug fixes, readme.

Allowed ./manage.py restore --media to restore the mysql database
and media folder from a backup made with rsync.

Changed requirements.txt to require a much newer version of pysftp
as the previous version did not support mkdir which was being used.

Clarified flag usage in readme file and added new example.
Merge pull request #12 from Ellipsis753/master

Added restore media for rsync backup. Bug fixes, readme.