Added implementation of intrinsicContentSize to support positioning in AutoLayout.
Added minHeight option to allow configuration of the height of the control. If set to less than the indicatorDiameter, the value will be set to the indicatorDiameter.
Reset minHeight when applying a built-in style rather than initializing it to 36.0f without regard to the style. While both styles use the same default height this may be useful to other styles in the future.
Updated intrinsic height to match UIPageControl for which the height is zero when the control is hidden as a result of having only one or zero pages.
Adjust minHeight if necessary when indicatorDiameter is set.
Modified calls to invalidateIntrinsicContentSize to ensure backwards compatibility with iOS 5.0.
Invalidate intrinsic content size when the minHeight is changed.
Merge pull request #17 from idpaterson/pull-requests/autolayout-support

Added support for AutoLayout matching UIPageControl