HTML-like text formatting tag parsing for UILabels and UIButtons on iOS, similar to TextView on Android (according to http://commonsware.com/blog/Android/2010/05/26/html-tags-supported-by-textview.html).
Currently supported tags are:
<b>, <u>, <i>, <sup>, <sub>, <strike>, <small>
Convert to Swift.
Update to iOS 10.
Write comparison with NSAttributedString's -[initWithData:options:documentAttributes:error] including comparison performance tests.