Make jstree node patterns consistent with other sortable values

[kimisgold]

Right now, jstree nodes break from the sortable value pattern in two ways: they do not have a means of providing "restore value" strings, and they do not hide other actions when marked for removal.

[jimsafley]

I've pushed the "jstree-improvements" branch, which is where we can collaborate on this. So far I've added the title and aria-label attributes to the icons, and I've toggled the visibility of the icons when a link is removed and restored.

One problem I'm facing is the interaction of remove/restore on child links. When I remove a link, all of its icons and the icons of its child links are hidden. This is expected and desirable. But when I collapse and expand one of these links, the icons reappear, and I'm not sure why. It could be some jsTree nonsense, but it could also be something to do with CSS. Would you take a look to see if the CSS controls this behavior?

[kimisgold]

I'm seeing that it's inline styles controlling the action icon visibility, so I think it's JS controlling the behavior.

[jimsafley]

It's the visibility of the .jstree-themeicon, .jstree-displaylink and .jstree-editlink-edit icons specifically that are the problem here. They are being hidden by JS, but they are being made visible by some unknown means.