Iterating over a byte file object using __iter__ is rather useless, and a bit confusing perhaps.

It'd be nice to propose two things:

1. Having __iter__ raise an exception if the file was opened with the "b" flag.

2. Adding a new by_bytes() method to file objects, which would return an iterator that yielded the next byte in the file, introducing the ability to write a similar `for byte in byte_file_obj.by_bytes()` that is currently possible when iterating by line over non-byte files.

It's quite easy to do (2) currently, obviously, but perhaps it's worthy of consideration for inclusion.