Added solution to Project Euler #7.
Added solution to Project Euler #7.

Worked around what seems to be a bug in rakudo's implementation
of .delete() on hashes.

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