Fix VK player
They added an iframe to the page and the extension tried to inject script into it. Closes #32.
I don't see how this breaks it, since an iframe is treated the same as a seperate tab in WebNowPlaying, and I assume WNP can't find anything inside said iframe, so it shouldn't be an issue.
If the issue was it throwing errors, then just the second change is enough, no?
If I leave only the second change, my console is no longer filled with errors, but the extension still doesn't work (connected but not updated). I can see that the script is injected into both the page and the iframe, so it's probably a bug.
Sorry this took so long. Merging and will release a new version on the webstores soon-ish.