[euler/prob009] add version using feed operators
[euler/prob009] add version using feed operators

stmuk/perl6-examples,perl6/perl6-examples,agentzh/perl6-examples,agentzh/perl6-examples,Quinny/perl6-examples,stmuk/perl6-examples,perl6/perl6-examples,perl6/perl6-examples,agentzh/perl6-examples,perl6/perl6-examples,shlomif/perl6-examples,stmuk/perl6-examples,Quinny/perl6-examples,shlomif/perl6-examples,Quinny/perl6-examples,shlomif/perl6-examples,shlomif/perl6-examples,shlomif/perl6-examples,Quinny/perl6-examples,stmuk/perl6-examples,perl6/perl6-examples,stmuk/perl6-examples,Quinny/perl6-examples