io.py is used for open() and sys.std{in,out,err}.
Note that this currently breaks about 25 tests.

 * all calls to functions in the string module (except maketrans)
 * everything from stropmodule except for maketrans() which is still used

which was removed.

Use string methods rather than the string module.

methods to incrementalcodecs.

Also forward port r54786 (fix the incremental
utf_8_sig decoder).

I'll add this step to PEP 306.

Don't read more than one line when reading text from a tty device.
Add peek() and read1() methods.
Return str instead of unicode when return ASCII characters in text mode.

Support ord(b) where b is a 1-byte string.
In zipfile.py, work around bytes being ints instead of chars, sometimes.

buffer-supporting objects (Unicode always excluded), and also of
str and bytes.
(For some reason u"" + b"" doesn't fail, I'll investigate later.)

Fix the truncate() semantics -- it should not affect the current position.
Switch wave.py/chunk.py to struct.unpack_from() to support bytes.
Don't use writelines() on binary files (test_fileinput.py).

not the number of array elements.

- 25% speed increse in tell();
- f.seek(0, 1) now maps to f.seek(f.tell(), 0) instead of to f.tell().

call self.buffer.tell().

Restore complex pickling.
Use cPickle in io.py.

without touching io.py or test_io.py.  The cause of the failure was that
bytes objects didn't pickle right.  As a stop-gap measure, I'm providing
bytes pickling via copy_reg.  Eventually, we should use a more efficient
protocol, e.g. __reduce_ex__ or __getstate__/__setstate__.

There is somewhat working (but slow) code supporting seek/tell for text files,
but extensive testing exposes a bug I can't nail down.

write() returns the number of bytes/characters written/buffered.
FileIO.close() calls self.flush().
Implement readinto() for buffered readers.
Tests th check all these.
Test proper behavior of __enter__/__exit__.

Reduce large file size to 2**31 (and a bit).

Etc., etc.