changelog for fix for Mouse
fix up prereqs for Mouse
adjust xt tests to match recent changes for Mouse method detection: Scalar::Util is special-cased

..because it turns out that Mouse::Meta::Module::get_method_list has a totally
bizarre idea of what constitutes one of its own methods:
https://github.com/gfx/p5-Mouse/blob/2.3.0/lib/Mouse/Meta/Module.pm#L78-81
avoid turning the main namespace into a Moose or Mouse class
namespace-autoclean-0.18

  - better method detection for Mouse (github #4, Graham Knop)