Converted dates are converted to string on parse

[fmluizao]

I18n::Alchemy::DateParser.parse("07/07/2015") => "2015-07-07"

From I18n::Alchemy::DateParser#parse, we have:

build_object(parsed_date).to_s

Why we need to convert the date back to string? I think it's better just return the Date object. ActiveRecord will not complain, and the parser would be more generic.

Thoughts?