%task15-1 - Added solution/in_words.rb
%task15-2 - Wrote ones,tens,teens
%task15-3 - Added num=self
%task15-4 - Added solution for 0<10
%task15-5 - Added solution tens,teens,ones
%task15-6 - Added solution from 0 to 100
%task15-7 - Need to fix if > 100
%task15-8 - Need to fix if number is Bignum
%task15-9 - Need to use include module for Bignum
%task15-9 - Used two classes Fixnum and Bignum which include one module Words