Add unit declarator to role declarations
Add unit declarator to role declarations

As of Rakudo 2015.05, the `unit` declarator is required before using
`module`, `class`, `role` or `grammar` declarations (unless it uses a
block).  Code still using the old blockless semicolon form will throw a
warning. This commit stops the warning from appearing in the new Rakudo.

teodozjan/perl-store