@ashfurrow => support passing objects between segues and  RAC tidying

Added ECPhoneNumberFormatter to format our phone numbers (probably need to check that the string length is > 6 - to ensure it's not a bid )

* Forced everything to use stubs ATM, made a moya issue around an odd issue I was getting.
* Removed some of the `public` bits.

* Used some of swift's block/function consolidation to make the RAC map methods named functions. I do not know if this creates a strong reference, my guess is that it doesn't. E.g. `RAC(nextBidAmountLabel, "text") <~ RACObserve(saleArtwork, "openingBidCents").map(openingBidString)`

* Added an equality operator to UISegueIdentifier so we can compare them to the known IDs in the prepare, lot less stringiness in our app code.
Hmm. Interesting syntactical choice. I kind of like it, but feel like it might encourage us to call those functions explicitly from a non-RAC context (it is tempting). What are your thoughts on scoping these functions to the `viewDidLoad` function instead?