Add support for finding out if you're the highest bidder

Our auction is ran async from the networking, so when we make a bid we do not know whether you have actually won or not. So we need to then do a check for the top bidder vs one of our bids. This means a seconds run of networking calls, and a look up through the bids.

also @1aurabrown had clued me in on the fact that we weren't going into bids correctly after registering post-bid, so I fixed that up too.

Once this is done there's a few different states that you can get into for finishing ( e.g. should we show you your bidder details ) your bidding process. I'm afraid a lot of that is state-ful code, it got a bit hard trying to deal with a lot of `then` and RAC `if`s - so I ditched it. :snowman: 

Updates to today's CocoaPods, this should fix the annoying "must restart xcode" thing.


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