Fix up some encoding issues

The commits run in order from most sane to least sane -- and definitely the work in MetaYAML.pm should be reworked for efficiency. BUT - this (coupled with a local patch to [ReadmeAnyFromPod that also sets :utf8 when calling out to File::Slurp) actually produced a sane dist with Russian and Japanese characters added to metadata and pod via multiple plugins. Module.pm, META.json and META.yml all came out pristine.

Also the last commit will probably have knock-on effects with other plugins, so anything resembling those changes should be done in a development release first!