Fixes and Housekeeping

Patches

• Added lazy loading explanation to readme: #1015
• Remove unused css class hidden: #1049
• Fix snapping of circle center marker: #1036
• Send pm:update after marker is edited: #1044
• Fix dragging in canvas mode: #1046
• Fix fire vertex removed event: #1028
• Bump required node version to >=16 && <17

Credits

Huge thanks to @mcepo, @Falke-Design, and @lmachens for helping!