docs(nav): highlight current nav-index-listing

Color the current nav-index-listing item dark red
to make it easier to know where you are.

Closes #9970
Closes #9974
fix($http): don't parse single space responses as JSON

Closes #9907
feat($location): allow to location to be changed during $locationChangeStart

Closes #9607
Closes #9678
fix(minErr): stringify non-JSON compatible objects in error messages

Fix the JSON stringification to output a more meaningful string when an
object cannot be normally converted to a JSON string, such as when the
object contains cyclic references that would cause `JSON.stringify()`
to throw an error.

Closes #10085
fix(ngRepeat): support cyclic object references in error messages

Now that `minErr` can cope with objects that cannot be normally stringified
to JSON, just pass the error arguments straight through without trying to
stringify them first.

Closes #9838
Closes #10065
Closes #10085
fix($rootScope): handle cyclic references in scopes when creating error messages

Use the new private function `stringify` to convert scope values to strings,
since this can cope with cyclic references and other oddities.

Closes #10085
docs(tutorial/step-4): "unknown" option is actually blank

The name 'unknown' doesn't appear as a choice, the new choice is just blank.
Side note: once I choose one of the non-blank options, I no longer see the blank option.

Closes #10079
docs(tutorial/step-5): include sort and filter in json view experiment

Closes #10082
docs($anchorScrollProvider): remove repeated word

Closes #10093
chore(docs): add favicon to docs app
fix($animate): applyStyles from options on leave

missing <code>[options]</code> API that should either be removed from
the docs or added in the code

@param {object=} options an optional collection of options that will be
applied to the element.

the tests weren't working for this feature
```javascript
$animate.leave(element, 'off', {
to: { color: 'blue' }
});
assertColor('blue'); //nothing should happen the element is gone anyway
```

you can view the docs here https://ng-click.com/$animate#leave