Added checks to prevent Same Origin Policy

[BrettSheleski]

I added this as we were hosting SCORM packages made by various authors but not using a SCORM engine on our site. We found that if another site happened open a SCO in a new tab/window it caused a Same Origin Policy security exception resulting in the content to not render.

I added a check to prevent this exception from occurring and instead return a null API object.

[Sangrene]

Thanks for this, spared me a few headaches ! Should merge.