* lang/python/gpgme.i: Adjust to Python3's string type being
'Unicode', not 'bytes'. Fix type checking.
* lang/python/core.py (Data.write): Add docstring mentioning the
expected type of parameter 'buffer'.
(Data.read): Adjust read loop. Also, use a saner chunk size, and join
all chunks at the end instead of adding them.
* lang/python/examples/simple.py: Adjust example.
Signed-off-by: Justus Winter <justus@gnupg.org>
