[TIMOB-7873] iOS: Anchor point affects pinning

In iOS, setting the anchorPoint property of a view's layer influences how it is laid out with respect to the geometry of the containing view. It does not affect "just transforms" on the object (in actuality, it's affecting the identity transform), but also the ability to pin l/r/t/b on views. From Blain in IRC as an example: bq. Position should be clarified. On iOS, position is defined by the anchorpoint, which defaults to 0.5, 0.5. That is, for an object whose top is 50, left is 50, bottom is 100, and right is 100, x=75, y=75. If the anchorpoint was changed to 0,0, the same object with given top/left/bottom/right bounds's x and y would be 50. If the anchorpoint is 1,1, the same object's x and y would be 100. See: https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreAnimation_guide/Articles/Layers.html#//apple_ref/doc/uid/TP40006082-SW9