Update to 2.2.110

Changelog:

• Fix {(substr )} markup expression with non-number arguments could cause warnings.
• Add $PageListSortCmpFunction, default to current 'strcasecmp'.
• Add global $MarkupMarkupLevel which changes when the processing is inside (:markup:) blocks.
• Fix inconsistent white space with inline [@escaped code@].
• Update documentation.

Sponsored by: Netzkommune GmbH