Way to ignore elements for protectEditing #16
Description
Follow on from #15
Right now the protectEditing flag disables pointer events on all non-simpla elements whilst editable. This means that it's impossible for a dev to create custom edit UI for Simpla and have it play nice with simpla-admin's edit click protection.
We should expose a method for developers to earmark element trees as Simpla editable, to be ignored by protectEditing if they want them to work with it.
Cleanest way is probably just a dumb data attribute that we do a check for in the tree walker, something like data-simpla-editable.