* Add Hadiyya, Gedeo, Oromo data after reviewing ethiopic calendar usage.

* Add getTsome method which checks if the object day, or args, is a tsome.

* Eventually implement Gurage, Oromo and Sidama calendar systems.

* Add ጾመ ገሀድ detection based on ትንሣኤ.

* Add methods for holidays.  Consider islamic holidays (complicated by
  lunar calendar).

* Complete formatting methods.  Don't forget ethiopic hour difference.

* Fill out documentation.
