Version 0.13.0

• Add support for Python 3.6.
• Drop support for Python 2.6/3.3.
• Return generator instead of list for Arrow.range(), Arrow.span_range() and Arrow.interval().
• Fix arrow.get() to work with str & tzinfo combo.
• Make sure special RegEx characters are escaped in format string.
• Add support for ZZZ when formatting.
• Stop using datetime.utcnow() in internals, use datetime.now(UTC) instead.
• Return NotImplemented instead of TypeError in arrow math internals.
• Added Estonian Locale.
• Small fixes to Greek locale.
• TagalogLocale improvements.
• Add test requirements to setup.
• Improve docs for get, now and utcnow methods.
• Fix typo in depreciation warning.