ePub syntax error, class attribute redefined on anchor tags is the source file's tag has an existing class.

[dotHTM]

Running pandoc on HTML content where a href tags have a class, pandoc adds another class attribute which is not allowed in ePub output in at least two ePub readers (iBooks, Kitabu). Both tested readers report errors related to "Attribute class redefined"

Sample command that exhibits this issue:
pandoc http://search.cpan.org/~timb/DBI-1.636/DBI.pm -o dbi.cpan.epub

Where some anchor tags contain the attribute class="podlinkurl" and the same link tag in the output ePub chapter 1 HTML file reads class="uri" class="podlinkurl" where the ePub render error points out the redefined attribute.

Work around is to curl the link, then search/replace via perl, sed, etc to remove the existing class attributes on a href tags and then pipe into pandoc for conversion.

Current versions:

• macOS 10.12.5
• iBooks 1.10
• Kitabu 1.1
• pandoc 1.19.2.1
  Compiled with pandoc-types 1.17.0.5, texmath 0.9, skylighting 0.1.1.4```