fix design of type.
bug fix: error is occured when select type label.
add prefix "textae-editor__" to css class name.
bug fix: selected relations is not unselected when a span or entity clicked without Ctrl key.
bug fix: the model data is updated even if an correspond DOM is not created.
a span of model data has reference to left/right span order by position.
model.annotationData can return range of Span.
we can add new span over exists spans.