When guessing, remove the dependency on the 'file' class and just use .read() instead. Didn't work on Python 3 anyway.
When guessing, remove the dependency on the 'file' class and
just use .read() instead. Didn't work on Python 3 anyway.

drj11/pypng,mnaberez/pypng,mnaberez/pypng,drj11/pypng,Scondo/purepng,Scondo/purepng