Remove videos; links open in current tab; general cleanup

I remember seeing this a while ago and thinking it was a neat idea.  Never played with a chrome extension before, so I thought it would be an interesting thing to look into.

Did some cleanup of various files, fixing things like spacing (trailing, tabs/spaces mixed, etc) and missing semicolons.  Removed comparisons to undefined, since it can make for awkward situations.  Added early returns to make sure that a function stops when it is supposed to.

Changed the way links are clicked from using `.click()` to just modifying `window.location`.  That way it will open up in the current window, instead of sometimes going to a new tab.

Extension now removes videos (or tries to) when visiting pages. This is so random audio doesn't start in the background.

Thanks for the code!