Moved the SECRET_KEY out of settings.py and moved into the local config
file as reccommended in issue #1.
Added a placeholder email_settings, which provides an example of what is
needed by other developers. The .gitignore still contains
email_settings.* so that sensitive email data doesn't get pushed up.
Closes #1. Install docs changed to reflect new position of SECRET_KEY in
local config file - and out of settings.py