Consolidate vote list

First iteration of merging all the voter listing into a single accordion version.

A couple of important TODO's.

1. [Include parties in the list even if the whole party was absent](https://github.com/openaustralia/publicwhip/blob/83166170072273d800f0c641831e772adc32f9d3/app/views/divisions/_summary.html.haml#L13)
2. [Order the voters with a party rebels first, then majority, then absent](https://github.com/openaustralia/publicwhip/blob/83166170072273d800f0c641831e772adc32f9d3/app/views/divisions/_summary.html.haml#L25)

I also think independents need to get elevated to be shown at the level of parties, at the moment it seems like they're an independent's party ([See Issue #290](https://github.com/openaustralia/publicwhip/issues/290#issuecomment-52728199) for discussion). Similarly there's the [issue of President etc. getting pulled out of their parties](https://github.com/openaustralia/publicwhip/issues/4).