W3lib

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- w3lib.http.basic_auth_header now returns bytes

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- add support for big5-hkscs encoding.

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- PY3 fixed headers_raw_to_dict and headers_dict_to_raw;
- documentation improvements;
- provide wheels.

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- w3lib.form.encode_multipart is deprecated;
- docstrings and docs are improved;
- w3lib.url.add_or_replace_parameter is re-implemented on top of
stdlib functions;
- remove_entities is renamed to replace_entities.

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- Python 2.6 support is dropped.

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- Python 3 support;
- get_meta_refresh encoding handling is fixed;
- check for '?' in add_or_replace_parameter;
- ISO-8859-1 is used for HTTP Basic Auth;
- fixed unicode handling in replace_escape_chars;