Update libtidy to version 5.8.0 final. Main changes:
Add IMG loading and SVG paint attributes.
Add HTML5 extended color names.
New <title> element clean up and warnings.
Fix multiple bugs, integer overflows, access violations, and memory leaks.
Add the TidyCloseQuotedValuesAtGt option to close a quoted value prematurely if there is a “>” character before or instead of the closing quote character.