removing frames with type 1
forward pointers point to the next packet (=size of the packet) instead of pointing over several type 0 frames
removing forward pointers from type 2 frames (they are after the above changes equal to the data_size and would thus be redundant)
simplify frame_code flags 7->5 bit
remove zero_bit definition (was unused)
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@12239 b3059339-0415-0410-9bf9-f77b7e298cf2