Simple Poll Module

This adds a simple poll module.

In order to use it, you have to bind the following commands:

`pollctl: Poll.PollCtl()`
`vote: Poll.Vote()`

This module is far away from being perfect. There is still a lot to be done like getting rid of the global poll storage variable or adding jid based user identification. However, its current state may already be useful to some people. Feel free to fix or report any problems you encounter.