Teardown api proxies when exiting the remote sandbox
README formatting, document manage.py, update setup instructions.

- Documentation for --sandbox argumrnt for manage.py.
- Remove documentation for optional path setup over which we have no control.
- Remove mentions of 'remote' command.
Line breaks in TODO.md
Deploy command not on the roadmap - use appcfg update as normal
Remove boot.py - users should use djangae.core.management instead.
Oh yeah, 'see' isn't a good name for a link. :D