Updated to 2.21

Upstream changes:
2.21 Mar 16 2014
        - sync with Debian patches - RT#91658
        - fix copyright and license entries - RT#43463

2.20 Feb 03 2014
        - drop t/v1*.t unit tests due to license issue
          https://github.com/renormalist/class-methodmaker/issues/2

2.19 Dec 15 2013
        - Fix 5.19 incompatibility - RT#88934 (Zefram)
        - small distro polishing

(wen)