Update babel to 2.6.0

[pyup-bot]

This PR updates Babel from 2.5.3 to 2.6.0.

Changelog

2.6.0

-------------

Possibly incompatible changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

These may be backward incompatible in some cases, as some more-or-less internal APIs have changed.
Please feel free to file issues if you bump into anything strange and we'll try to help!

* Numbers: Refactor decimal handling code and allow bypass of decimal quantization. (kdeldycke) (PR 538)
* Messages: allow processing files that are in locales unknown to Babel (akx) (PR 557)
* General: Drop support for EOL Python 2.6 and 3.3 (hugovk) (PR 546)

Other changes
~~~~~~~~~~~~~

* CLDR: Use CLDR 33 (akx) (PR 581)
* Lists: Add support for various list styles other than the default (akx) (552)
* Messages: Add new PoFileError exception (Bedrock02) (PR 532)
* Times: Simplify Linux distro specific explicit timezone setting search (scop) (PR 528)

Bugfixes
~~~~~~~~

* CLDR: avoid importing alt=narrow currency symbols (akx) (PR 558)
* CLDR: ignore non-Latin numbering systems (akx) (PR 579)
* Docs: Fix improper example for date formatting (PTrottier) (PR 574)
* Tooling: Fix some deprecation warnings (akx) (PR 580)

Tooling & docs
~~~~~~~~~~~~~~

* Add explicit signatures to some date autofunctions (xmo-odoo) (PR 554)
* Include license file in the generated wheel package (jdufresne) (PR 539)
* Python 3.6 invalid escape sequence deprecation fixes (scop) (PR 528)
* Test and document all supported Python versions (jdufresne) (PR 540)
* Update copyright header years and authors file (akx) (PR 559)

Links

• PyPI: https://pypi.org/project/babel
• Changelog: https://pyup.io/changelogs/babel/
• Homepage: http://babel.pocoo.org/
• Docs: https://pythonhosted.org/Babel/