Ruby

date_core.c: moved some methods to DateTime

• ext/date/date_core.c (Init_date_core): moved methods which make
  sense only for DateTime to that class, instead of defining
  private methods in Date and making them public in DateTime.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66329 b2dd03c8-39d4-4d8f-98ff-823fe69b080e