Unknown code added to my site files

Hello,

I was in the process of adding something to my Header.php file when I noticed all this code that was not there before (please see image).

http://ow.ly/i/4KDmy

My site seems to be working fine (TheEdgeCode.com), but not sure what this can be doing to it.

So far I noticed only it on my header.php, functions.php and index.php. The other files seem to be ok.

Any idea what this is and how I can fix it?

Thanks!!