* Fix encoding for files created for building package (issue #1027)

This is minimal set of modifications, which fixed the problem.

There are still more places, where files are open in text mode
without explicit encoding, thus possibly failing on systems not using
UTF-8 console encoding.

* test_api.py use explicit encoding for files.

* get-poetry.py: fix explicit (utf-8) encoding for files open in text mode

* tests: fix explicit (utf-8) encoding for files open in text mode

* poetry init: use explicit utf-8 for created pyproject.toml

* installed: use explicit utf-8 for text files

* layouts: use explicit utf-8 for open text files

* spdx: explicit utf-8 for open text files

* pypi_repository: explicit utf-8 for open text files

* explicit utf-8 for json

* explicit utf-8 for metadata

* explicit utf-8 for requires.txt

* open files with explicit encoding in py27

* fix creation of poetry.bat on Windows

* Make get-poetry.py compatible to py2/3

* Blacked two files to pass linter test

* remove extranous encoding related comments

* rewert broken move of import related to ansible

* removed extraneous comments about opening files in UTF-8

* rewert ansible.release import (keep order of vars unchanged)

* Revert to original content (as it comes from external project)

* all vendored setup.py files in fixtures reverted back to org

Resolves: #1162

`poetry build` creates a whl file using `os.mkstemp`. The file is
created with very restrictive permissions. This commit ensures these are
normalized before the build starts.

Partly addresses https://github.com/sdispater/poetry/issues/671.

- Fix non-sha256 hashes retrieval
- Fix resolution of packages with Python 3 only wheel

* use symlinks in created venv by default on non-windows platforms. Issue #779

* Fixed test for deployments without venv module available.