server (pages): added a confirm flag on successful post: A new set is used in SATSession to keep flags. First flag is "confirm": it is set when some data have been posted (so a confirmation message can be displayed in template). If seen in session, the template "confirm" variable is set to True, and the flag is removed from session (a refresh of the page will not display the confirm message anymore).

try:
    from common.constants import Const as C
except ImportError:
    pass # import doesn't work at this stage with pyjamas
else:
    __version__ = C.APP_VERSION