Missing feature: callback hooks for directives

[tbosch]

attach: When all bindings have received their initial value and the node is connected to the document.body

detach: When the view is removed from document.body

[tbosch]

A related problem: get child directives in the DOM order and maybe also change their order in the DOM.

E.g. if a tab container wants to know or even reorder tab children that a use specified in the template.
The tabs might not use ng-repeat, i.e. they would not create new views

<tab-container>
  <tab id=1>
  <tab id=2>
  <tab id=3>
</tab-container>

This is again related to what ng-repeat does: adding/removing/moving nodes in the DOM