Transclude type multi-element, use this for ng-repeat

The patch adds a new transclude type multi-element to be able to handle transclusions that include more elements that the one with the directive. The transclusion type multi-element works in the following way.

When a directive is defined of the type multi-element, then Angular looks for matching attributes named "<directive name>-start" and <directive name>-end" and transcludes the entire block. If element where the directive is present does not contain the attribute "<directive name>-start" then the transclusion works just as the transclusion type "element"

E.g

The directive ng-repeat is of type multi-element when compiling the template below, the compiler will look for the attribute ng-repeat-start. Given that this is present, it will look for a matching hg-repeat-end attribute. When found the entire block will be used for the linking function

```html
<ul>
  <li ng-repeat-start ng-repeat="item in items">{{item.name}};</li>
  <li>{{item.number}};</li>
  <li ng-repeat-end>{{item.color}};</li>
</ul>
```