GoogleTagManager: ensure initial gtm.view does not occur before Window Load

[ninomichaels]

The apps currently may fire a synthetic pageview gtm.view event before the default Page View and Window Ready events.

1.) Delay (do not prevent) the synthetic pageview from firing until the default events fire.
2.) Add a initialPageview = 1 to the dataLayer for this initial synthetic pageView -- subsequent gtm.view events should reflect initalPageview = 0

[ninomichaels]

#22