-Added a SYNCHRO_START in DVDRead for each cell change to fix

-Added a SYNCHRO_START in DVDRead for each cell change to fix
multi-angle streams

-Changed seek function to prevent jump-at-will and to remove two bugs in
sector computing.

-Initialize some values in netlist (payload_discard wasn't which caused
frame dropping)

-Come back of multi-sector read which should make reading faster

Now, theyre should be very few reading error, and we have got back the
performance we had before my netlist polioting :p