@ashfurrow => Switch to CocoaPods for Test Deps, adds a Button class

![selfie-1](http://i.imgur.com/aYHA3Ry.gif)

* I've moved the `submodules/FBSnapshotTestCase` dep out into CocoaPods, so we can use others if we're interested too. Should make the Bots build.

* Added a Button class. It's not particularly functional functional, but I don't want to deal with more submodules  for RAC on a monday morning. Bunch of XCode config jiggering around some issues from synx last week. 

* Tests are not built redundantly on every app run. 
* Moved back to iOS 8 as the target.


Done

As an aside, maybe we can expand `Nimble-Snapshots` to allow us to write something like.

`expect(a).toHaveValidSnapshot()` && `expect(a).toRecordSnapshot()`

other options are like how I wrote my expectation in the list [view here](https://github.com/artsy/eidolon/blob/master/KioskTests/ListViewControllerTests.swift#L18) using the equality matchers. 

`expect(a) == Snapshot()` && `expect(a) >> Snapshot()`