Processing PYX data or file and write as SGML.

Changes for 0.05 - 2023-10-19T10:42:00+02:00

• Fix typo in doc.
• Improve doc in constructor.
• Improve texts in doc.
• Move bugtracker to github.
• Rename example file to better name.
• Update Module::Install to 1.21 version.
• Update copyright years.