Make CSSAuth more rubust, should now also work with drives that are not 100%
compliant to the SFF-8090 standard. AGID invalidation should now work,
allowing us to recover from hung / failed authentications. Corrected
CSSGetASF, it does not take an AGID argument. Move several data structures
from the dvdcss handle to local variables in CSSAuth. Remove CSSAuth as a
externaly visible function in css.c.