python bitshuffle/bitshuffle.py < file should work

[jyn514]

Would involve changing infer_mode. Should be fairly easy to change.

Jeremy:

I expected python bitshuffle/bitshuffle.py < file to [encode the input file]
if I put in an encoded file I would expect it to decode

Me:

for that we'd have to look through the file before we decode it
grep ((<<.*>>)) isn't terribly hard though

[jyn514]

Looking at this again, it's easy to to always encode but significantly harder to infer (since input may not always be grepable. Think I'll wait on smart inferrence until we handle #16 and #54