Example of message metadata:
---------------------------

$message["meta"]["mod_poll"] :

Array
(
    [question] => Why?
    [answers] => Array
        (
            [0] => Because
            [1] => Why not?
            [2] => I dunno
        )

    [votes] => Array
        (
            [0] => 35
            [1] => 2
            [2] => 0
        )

)

[votes] contains the number of votes received by each answer.
The message_id serves as the poll's id.


Example of user metadata:
------------------------

$user["mod_poll"] :

Array
(
    [voted] => Array
        (
            [1024] => 1
            [1035] => 4
        )

)

In this example, 1024 and 1035 are the message_ids of the polls, and 1 and 4 are
the indices of the answers the user voted for.
