Strategy to match on first or on all matches

[wende]

Thanks to @strategy the matchers will check all, or try the first one and stop finding next matches. That way You can put more specific matches before these less specific

# Possible values :one, :many. Defaults to nil
@strategy :one | :many | nil 

[koudelka]

Hey @wende, thanks for the PR! :)

Could you include some tests for the new functionality?

Also, some notes in the README would make this a complete PR.