Myriad improvements to the fileviewer code. Lines now get their own line...

I know this project hasn't seen a lot of movement lately, but I thought I'd help with the UX of the fileviewer module to make it a little bit more useful. I fixed a bug in the little JavaScript snippet to highlight the line linked to by the #lineN anchor, and now code lines are put into individual containers (which makes for a better-structured DOM) which highlight when hovered over.