Businesstime

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* Fix a bug (25) where holidays were not properly detected when later dates were tested before earlier ones, thanks agans
* Fix a bug (13) where time deltas were calculated incorrectly when both start and end times are after business hours, thanks airsource
* `businesstime_hours` now returns a `timedelta` rather than a numeric value (23), thanks naes17
* `businesstimedelta` now returns negative timedeltas when the start time is after the end time (19), thanks jeremyklein
* Add 2017-2018 public holidays for Queensland/Brisbane Australia (17), thanks danc86

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* Fix broken pypi package (14), thanks tarkatronic

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* Change package layout: country-specific holidays are stored in files named w/ their ISO 3166-1 alpha-3 country codes
* Add 2013-2016 public holidays for Queensland/Brisbane Australia (11), from danc86
* Fix AttributeError when no holidays are specified (10), from danc86

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* Handle US federal holidays that fall on the weekend but are observed on Friday/Monday (8)

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* Fixed a bug (7) where a datetime after business hours and a datetime during business hours were handled incorrectly

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* Fixed a bug (6) where two datetimes on the same day but before business hours were handled incorrectly