LwDITA 5.7.0

What's Changed

• Refactor AST test resources by @jelovirt in #198
• Fix footnote generation by @jelovirt in #206
• Use @type in audience by @jelovirt in #207
• Table block content by @jelovirt in #200
• Add support for Markdown output for footnote by @jelovirt in #208
• Fix table bugs by @jelovirt in #209
• Fix duplicate class attribute in specialization filter by @jelovirt in #210

Full Changelog: 5.6.0...5.7.0