Changed WebCore to pull from GitHub instead of GoogleCode.

The WebCore repo can now be specified in config as a .zip file.
checkWebCore will pull the .zip file, extract it, and move the contents to the WebHostRoot as needed.

I would recommend creating https://github.com/CellAO/CellAO-WebCore and updating Config.xml with it, as I've currently got it set to https://github.com/gaddie-3/CellAO-WebCore