fix(start()): locate parent before every 'start()'

When the ng-view is attached to the body
And the route is changed
The the body may be re-written out from under the loading bar
And the $parent object will be invalid

By finding the $parent every time the loading bar is started,
it ensures that the <div> elements aren't attached to a stale
parent.
Merge branch 'networkerror-master'
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