Prevent "popping" when transition using entrance

Simply moved the .scrollTop code so it doesn't fire until after the old
view has faded out, which prevents a visual "pop" as the page scrolls to
the top right before starting the transition.
Merge pull request #66 from upta/master

Prevent "popping" when transition using entrance
Merge branch 'master' of github.com:BlueSpire/Durandal