Introduce writef() and writestr() method

[miurahr]

Implement a feature request #248 and #290

• writestr(str_or_bytes, arcname: str) accept str or bytes family data for compression.
  when receiving str as argument, it encode it into UTF-8
• writef(BytesIO_or_binary_fileobject, arcname: str) accept io.BytesIO() memory buffer or file object with open(mode='rb')

Signed-off-by: Hiroshi Miura miurahr@linux.com

[coveralls]

Coverage increased (+0.06%) to 90.034% when pulling 0518c80 on topic-writestr into 41c2ff8 on master.

[hildogjr]

Just following up this merge-request. Two question:

1. When this will be on PyPI?
2. Should we change the order of the input parameters to better match with zipfile Python library? As discussion on writestr support just like ZipFile.writestr #290 we have ZipFile.writestr(zinfo_or_arcname, data, compress_type=None, compresslevel=None) on this implementation was used def writestr(self, data: Union[bytes, bytearray, memoryview], arcname: str) (the opposite order, it is the same case with tarfile Python module).