hevc_parser: Set pict_type, key_frame and output_picture_number.
hevc: Search start code in decode_nal_units().

User may cut off a weird position and send a packet from there.
This avoids returning as invalid data immediately.
hevc: Remove disable_au.

This hack is now unneeded.
hevc: Fix typo of the condition to set pocTid0.
hevc: Add IS_NONREF macro to check if sub-layer non-reference picture.
hevc: Fix typos of NAL_BLA_N_LP for NAL_BLA_W_RADL.
hevc: use long exp golomb function