Added spec helpers to trigger gesture recognizers in views

The goal of this was to provide a method for tests to trigger gestures that have been added to UIViews, similar to how you can call -tap on a UIButton. It turns out, this is kind of complicated, but we think the changes we made are valuable. 

This Pull Request:

* fixes what we believe was a possible error in memory management in the UIWindow+Spec tests
* refactors a fixture to use cedar spies, adds a `-recognize` method to UIGestureRecognizers
* adds `-tap`, `-swipe`, and `-pinch` methods to UIView
* backfills some tests for an existing untested UIView category method

Let us know if you'd like us to split this up at all.

The methods we added to UIView call the `-recognize` method on the appropriate UIGestureRecognizers. The `-recognize` method was added at the abstract UIGestureRecognizer level, and simply performs the selector(s) on the target(s).

We wanted to use the cool method swizzling methods defined in NSObject+MethodRedirection.h, but it was very hard to actually get UIKit to link against the static Foundation+PivotalCoreKit lib, so we reimplemented the necessary methods for now. It seems like linking against the Foundation+PCK lib would be the best thing, but we were unsure if that was even desirable, or how to even get the build to work, given that the frameworks have custom build directories. If you can suggest a way to go about achieving this, we'd be happy to pursue doing so.