docs(guide/index): replace "shold" to "should"

Replace "shold" to "should"

Closes #6216
refactor(ngTransclude): use transclusion function passed in to link

Since we now pass in the transclusion function directly to the link function, we no longer need
the old scheme whereby we saved the transclude function injected into the controller for later
use in during linking.

Additionally, this change may aid in correcting a memory leak of detached DOM nodes (see #6181
for details).

This commit removes the controller and simplifies ngTransclude.

Closes #5375
Closes #6181
feat(filterFilter): support deeply nested predicate objects

Due to 339a165, it became impossible to filter nested properties of an object using the filterFilter.
A proposed solution to this was to enable the use of nested predicate objects. This change enables the
use of these nested predicate objects.

Example:

```html
<div ng-repeat="it in items | filter:{ address: { country: 'Canuckistan'}}"></div>
```

Or

```js
$filter('filter')(items, { address: { country: 'Canuckistan' } });
```

Closes #6215
Related to #6009