v1.3.3

• Allow Data URI images in Asciidoctor input: closes #109
• Document relations in document header -- include document title: #58
• Allow inequalities: metanorma/metanorma-itu#24
• Enforce consistent normalisation of relaton dashes: 69a5120
• Introduce subsequence attributes: metanorma/metanorma-itu#23
• Latex prerequisite enforcement: e82be47
• html5rubymacro asciidoctor extension support: #73
• Add table/@summary: metanorma/metanorma-nist#143
• Basicdoc grammar update
• Better handling of MathML passed in to Asciidoc: #111
• Fix image/* data URLs: #120