Update to 1.4

• Fix a bug in rendering nested block lists
• Fix build with GCC 6 and other minor warnings
• Build a static library too
• Significantly improve documentation
• Improvement of mkd2man
• Add an amalgamation (C sources to include directly in a project) (not included in the port though)

PR: 211330
Submitted by: Natacha Porté <natbsd@instinctive.eu> (maintainer & upstream)