v1.0.0-beta.18

• fix: pin HeaderTabs version
• fix: switch to SMW dev branch to include various fixes
• fix: switch back to WSSlots org repo
• fix: re-add PageForms
• Extension:MwJson
  • fix: adapt getSemanticProperties to SMW >= 5.0.0
  • fix: disable the criteria 'extended' in json-schema-ref-parser
• Extension:OpenSemanticLab
  • fix: fix autocomplete in VE LinkEdit template
• Extension:WikiMarkdown
  • fix Error: Class "ParsedownExtended" not found