Fix for issues arising from pull request #458

This should fix the issue with saving/loading the saved server list. As well as fixing the core issue (incorrect call to Cryptocat.Storage.getItem), I've stored the bosh/xmpp data directly in the select option using data-* attributes. This should simplify both the logic and the code, as it removes the need to maintain a separate data structure alongside the list itself.

I hope this resolves the issues from #458!