Added UIEvent+KIFAssociations.

Convenience methods for associating touch object(s) with UIEvents.
Added KIFUIPanGestureVelocitySample.

Provides mechanism for generating UIPanGestureVelocitySamples.
Added UITouch+KIFExposers.

Provides readwrite access to _locationInWindow and _previousLocationInWindow ivars on UITouch.
Added UIPanGestureRecognizer+KIFExposers.

Provides readwrite access to _velocitySample and _previousVelocitySample.  Since the class of these ivars (UIPanGestureVelocitySample) is private, we make use of the KIFUIPanGestureVelocitySample class.
Added NSObject categories BNRCopying and BNRIvarConvenience.

-bnr_shallowCopy provides a mechanism to copy (most of) an instance of a class which does not implement copyWithZone:.  The copy is "shallow" in the sense that objects are not copied recursively.
Fixed a couple of issues with NSObject+BNRAssociatedDictionary.
Added methods to KIFTestStep allowing calling code to specify displacement of swipes rather than be limited to specifying direction only.
Added UIPanGestureRecognizer+KIFOverrides.

KIF swipes in pan gesture recognizers now have velocity.