Making the python streamcorpus 17x faster :-)

Learned that TBinaryProtocolAccelerated is the interface to use when
fastbinary is available.  This now checks whether fastbinary is
available for import, and if so it uses TBinaryProtocolAccelerated,
otherwise it falls back to TBinaryProtocol

This required adding a "readAll" method to md5_file -- see inline
comments.