Wsgidav

- Improve configuration files:
- YAML is now the preferred configuration file format.
- Add support for JSON config files (JavaScript-style comments allowed) (89)
- Use wsgidav.yaml, wsgidav.json, or wsgidav.conf by default if they exist in the local folder
- Expand '~' in `--root` and `--config` command line options
- 97: Fix assumption that QUERY_STRING is in environment (dir_browser)
- 99: Fix virtual_dav_provider for Py3: WSGI expects binary instead of str
- 100: Send ETags with PUT response
- 101: Fail cleanly if trying to PUT to unknown collection
- Refactor logging:
- Re-define verbosity level range: 0..5
- Remove usage of `print` in favor of `logging.getLogger().debug`
- Remove util.note(), .status(), ... helpers
- Refactor code base:
- Use `.format()` syntax instead of `%s` for string templating
- Mandatory PEP 8 compliance (checked by flake8)
- Rework documentation on Read The Docs
- MSI setup uses Cheroot version 6.2+

- 80: Drop support for Python 3.3 (end-of-life September 2017)
- 86: Give custom PropertyManager implementations access to the environ
- 87: Don't assume sys.stdout.encoding is not None
- 90: Custom response headers
- 93: Add support for streaming large files on Mac

- Fix 75: Return 401 when auth method is not supported
- Fix 77: removeProperty call to not lose dryRun, otherwise removeProperty is
called twice for real
- Fix 79: Prevent error when missing environment variable

- 69: Rectifying naming disparity for CherryPy server
- Fix 67: lock manager returns timeout negative seconds
- Fix 71: Attempts to unlock a nonexistent resource cause an internal server error
- Fix 73: Failed on processing non-iso-8859-1 characters on Python 3
- MSI setup uses Python 3.5

- 65: Support for Cheroot server, which is the standalone WSGI server of CherryPy
since version 9.0.
`--server=cheroot` is the default now.
- New option `--ssl-adapter`, used by 'cheroot' server if SSL certificates are
configured. Defaults to 'builtin'.<br>
Set to 'pyopenssl' to use an existing OpenSSL installation.
(Note: Currently broken as of Cheroot 5.1, see cherrypy/cheroot6)
- Deprecate cherrypy.wsgiserver.<br>
`--server=cherrypy` was renamed to `--server=cherrypy-wsgiserver`
- 64: Fix LOCK without owner
- 65: Add lxml to MSI installer
- Release as Wheel

- 42: Remove some print usage in favor of logging (Sergi Almacellas Abellana)
- 43: PEP 8 fixes (Sergi Almacellas Abellana, Tom Viner)
- 45 New method `_DAVResource.finalizeHeaders(environ, responseHeaders)` (Samuel Fekete)
- 55 Custom response handlers for PUT, GET etc.
- New helpers `addons.stream_tools.FileLikeQueue` and `StreamingFile` allow to
pipe / proxy PUT requests to external consumers.