Made relative path option

I added a relative path option to gbox. This hasn't changed any logic anywhere, but it allows me to put the library anywhere I like (in a /lib/ folder, specifically). You set the gbox._relpath option before any calls to the libraries, including help.

Previously, loadAll() wouldn't to find the debug font if the directory was anything buy akihabara/, and silently fail. There's also a few places where I expect the same would happen in the help.js script too, so I've changed those. I didn't see any other references to "akihabara/" elsewhere that would need changing.