Fix font-face names and paths

Mobile web compile incorrectly adds fonts found in android, iphone,
blackberry, etc folders.

Is should only look in the "mobileweb" folder.

It also doesn't correctly set up the paths for these fonts. This is due
to:

1. An assumption that the directory separator is always "/"  On windows
it is "\"
2. "mobileweb/fonts/fontname.otf" is the path created, when the path
should just be "/fonts/fontname.otf"