Fixed: initial load has proper padding and loads to proper point

-getYOffset/getXOffset now takes an optional pageIndex parameter (that is otherwise interpreted as currentPageIndex if undefined) to get the offset of the page that will be navigated to

-removed some extra calculations that I'm not sure why I had in here originally

-moved some padding calculations to where they will only be called once

-produced the face palm heard round the world for
"var heightSoFar = settings.horizontalPadding;
var widthSoFar = settings.verticalPadding;"

-added some safeties so that settings.goDirectlyTo and settings.currentPageIndex are sure to exist after/while viewer is being setup

Closes #211