Support non-ASCII characters and triple dotted initials

* Allow any Unicode 'alpha' char where we once only allowed A-Z
* Support names like "M.E.E. Ericson"
* Add Gemfile & update Rakefile for Rake 10
* Add still-incomplete specs (based on my particular use case)

I'm aware that this mixes several changes in a way that might be annoying to accept. If you'd like me to split it up, let me know in what pieces.