Fix tooltip positioning with regards to viewports

The getPosition function was simplified with a new function,
getViewportBounds, was added to specifically
tackle the cases where we’re looking for the viewport bounds.

‘absolute’ and ‘fixed’ tooltips are now matched against the screen
where other ones are made to fit inside the viewport element.
Again, resources posted below. I don't think its worth talking about optimization and speed on such a scale. (Talking about scale again, hopefully that doesn't work out like last time.)