Handle multiple delegated selectors on tooltip and popover nodes

Fixes #14167.  This change just stores an hash of multiple tooltip or popover objects on the node when a selector is provided.  I wasn't sure whether to use an array or a hash, but I went with a hash indexed by the selector so that I could preserve the behavior that you cannot reinitialize a node with the same selector.
Please place each property in these objects on a new line, to stay consistent with the rest of the file.

```js
.bootstrapPopover({
  selector: 'a.first',
  trigger: 'click'
})
```