#3 mpeg header reader bug

[David Norris]

The code that reads MPEG header data from an MP3 file
could possibly fail on some files. The code looks for
the sync signal in the MP3 datastream (namely eleven
consecutive 1-bits starting on a byte boundary).
Because of the way the code buffers blocks of the file
at a time, a sync signal that extends across a block
boundary will not be recognized since both blocks are
never loaded at the same time. It's unlikely this will
occur in an actual file, but it easily could and
should be fixed.