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Stacks - Using stack views (requires iOS 9)

Version 1.1   06 July 2015   Adapting axis to view size classes
Version 1.0   22 June 2015   Initial version.
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Example of how to use UIStackView to simplify layout of horizontal and
vertical arrangements of views. See the following post for details:

http://useyourloaf.com/blog/2015/06/21/easier-autolayout-with-stackviews.html

Also see this post for details on how to have the stack view automatically
adapt to size class changes:

http://useyourloaf.com/blog/2015/07/06/adapting-stack-views-with-size-classes.html