Workalendar

- Added Portugal, thx to borfast (110).

- Added Colombia calendar, thx to spalac24
- Added Slovakia calendar, thx to Adman
- Fixed the Boxing day & boxing day shift for Australia

- Germany calendar added, thx to rndusr
- Support building on systems where LANG=C (Ubuntu) 92
- little improvement to directly return a tested value.
- ``delta`` argument for ``add_working_days()`` can be negative. added a
``sub_working_days()`` method that computes working days backwards.
- BUGFIX: shifting UK boxing day if Christmas day falls on a Friday (shit to
next Monday) 95
- BUGFIX: Renaming the Finnish "Independance Day" 101 (thx to
mikko-ahlroth-vincit)
- BUGFIX: Renaming Showa Day. "ō is not romji" 100 (thx shinriyo)
- BUGFIX: Belgian National Day title 99 (thx laulaz)

- How to contribute documentation,
- Added Belgium, European Central Bank, Sweden, every specific calendar in the
United States of America, Canada.
- BUGFIX: fixed a corpus christi bug. This day used to be included in every
ChristianMixin calendar, except noticed otherwise. Now it's not included by
default and should be set to "True" when needed.

- added LunarCalendar, including lunar month calculations
- added SouthKoreanCalendar, for a LunarCalendar proof of concept
- added Python3 support
- added Algeria, Australia, Brazil, Chile, Czech Republic, Finland,
France Alsace-Moselle, Greece, Hungary, Iceland, Italy, Ivory Coast, Japan,
Madagascar, Marshall Islands, Mexico, Northern Ireland, Norway, Panama,
Poland, Qatar, South Africa, São Tomé, Taiwan, United Kingdom calendars.
- BACKWARDS INCOMPATIBILITY: calendar suffix for class names are now obsolete.
e.g: to use the Japan calendar, simply import `workalendar.asia.Japan` instead
of JapanCalendar.

- First released version
- Core calendar classes, Western (European and North American)
easter computations,
- United States federal days
- France legal holidays days