Version 6.21.0

Changelog for version 6.21.0

Title	Description	Ticket
TeX and Math are NOT internal anymore; made PI-type internal		XCD-699
Add accessibility features		XCD-717
Color picker improvements	Added transform function to color picker button and input field Added `style` config to simple color picker, which can be set to: `grid`: Display colors in a grid layout `list`: Display colors and color names in a list layout	XED00016
Added Document::splitNodeUntil function & extended Element::mergeChildrenByTypes		XCD-50
Add destory function to editor		XCD-624

Title	Description	Ticket
Fixed issues in TextLengthCounter		XED-71
Added remove color button to color picker		XED-77
Fixed issue in ValidationManager which caused an error when the reviewbar is disabled		XED-80
Contextmenu is now Srollable		XCD-451
Fixed issue in ClipboardManager::parseHTML ('text/xml' -> 'text/html')		XED-00043
Fixed issue in ValidationManager which caused multiple errors on the same element to be lost		XED-00051
Updated table cell roles to enable the insert menus via breadcrumb, etc.		XED00028
null	null	null
Fixed issues in Element::insertSibling & added 'forward' parameter to Document::insertElements	Fixed issues in `Element::insertSibling` which caused siblings to be inserted at wrong references Added 'forward' parameter to `Document::insertElements`	XED-00052
Fixed inline element in root node causing errors with document splitting		XED-00060
Fixed unbind of dragDropManager not unbinding dragStart event		XED-00069
null	null	null
Fixed NaN issue in TextLengthCounter		XED-71
Fixed RawEditor wait message doesnt disappear		XCD-762
null	null	null
Fix issues in HistoryManager::onInsertOrEditButtonClick		XCD-745
Fixed issue with ribbons	Fixed an issue where the hide reviewbar button and the reviewbar options buttons wouldn't work when using ribbons in the external toolbar	XCD-799