UnsupportedHTML: Loosing Styles applied to Empty Paragraphs

[jleandroperez]

Details:

Empty Paragraphs, when analyzed by NSAttributedStringToNodes, currently produce no ElementNodes. All of their metadata is being lost.

Input:

<span><br>Here!</span>

Output:

<br><span>Here!</span>

Note that the span wrapping for the line break is being lost.

[jleandroperez]

Closed via #674