Adresses #742 and #239

https://docs.python.org/2/library/zipfile.html#zipfile.ZipFile.writestr

Note: When passing a ZipInfo instance as the zinfo_or_arcname parameter,
the compression method used will be that specified in the compress_type
member of the given ZipInfo instance. By default, the ZipInfo
constructor sets this member to ZIP_STORED.

* fixing #724

* added test for issue 724

* Add info about path dependencies being installed in editable mode
according to information here:
https://github.com/sdispater/poetry/issues/519#issuecomment-440028167

* Fix missing verb in doc

Co-Authored-By: germn <germn@users.noreply.github.com>

* Fix authentication failure for some APIs

Fixes an issue which occurs when APIs return authentication information in the URLs embedded in JSON responses.

* Test authentication on same host with duplicated credentials

Add test to ensure that basic authentication credentials in request URLs does not break authentication when they credentials match. This test purposefully does not examine program behavior when URL credentials and session credentials are different.