addConstraintsWithVisualFormats:options:, fixed UIEdgeInsetsForRectSubtractingRect.

[ADDED]     -[UIView addConstraintsWithVisualFormats:options:metrics:views:] convenience method for adding constraints to a view container.
[FIXED]     Don't inset edge when insect rect doesn't reach other edge (to avoid both edges being inset by the same rect).
[FIXED]     enumerateSubviews: -> enumerateViews: now also tries self.