Tokentextarea2: Create a single function that actually removes buttons
Tokentextarea2: Unconditional _adjustWidth() upon remove
Tokentextarea2: _adjustWidth() handles hidden case, simplifying code
Tokentextarea2: Do not call _adjustWidth() from add and remove functions
Tokentextarea2: Renaming _renameButtons() to _remove()
Tokentextarea2: Adding extension to sync to existing input
Tokentextarea2: Add tests for sync extension
Tokentextarea2: Add convenience classes for sync