Read-only mode is a setting an admin can enable to prevent writes to

the database. This can be used when the site is under maintenence or

being upgraded. This commit adds a decorator that wraps

login_required. If no arguments are passed into the new 

login_required it will behave the same as django's login_required.

If a boolean value for redirect_read_only is set to true, a decorator

that checks whether the user is in read-only mode and should redirect 

will be returned.
"New Review Request" and "My Accounts" now redirect to a Read-Only page

and "Register" redirects to "Log-in". Buttons to these pages are

removed for users affected in read-only mode.

Check that accessing New Review Request and My Accounts redirects to

503 page logged in as non-admin in read-only mode
Check that accessing Register when logged in or not redirects to the

log-in page
Check that links to New Review/My Accounts/Register are removed for

non-admins/unauthenticated users
Check that submitting Register form when in read-only mode does not

do any writes