Log Message:
Update to 0.19

Upstream changes:
0.19     2012-01-17

- The 0.17 release broke compatibility with pre-2.0 versions of Moose.

0.18     2012-01-10

- A small internal tweak which prevents the MooseX::ClassCompositor tests from
  failing.

0.17     2012-01-04

- Added a small optimization for an immutable constructor when used with Moose
  2.00+. The list of valid attributes is only generated once, rather than each
  time the constructor is run. Reported by Chip Salzenberg. RT #73664.