Adding a separate option that allows administrators to choose whether to store if...

Adding a separate option that allows administrators to choose whether to store if the greeting message has been shown in a cookie or in the session. This way users won't see the greeting message when they simply logout, because the greeting_set boolean is stored not in the session, but in a cookie. Separate middleware has been added that handles the Django cookies and passes all keys from the request.COOKIES object to the response object. This way the session cookies are stored as real HTTP cookies.

git-svn-id: http://svn.osqa.net/svnroot/osqa/trunk@1040 0cfe37f9-358a-4d5e-be75-b63607b5c754