Support for I18n

Please find attached a patch which adds I18n support.

By the way, the latest changes introduced to the recaptcha rendered the rdoc incorrect. It's impossible to use verify_recaptcha(@model) now, you have rather use verify_recaptcha(:model => @model). I wasted some time in order to understand, why I'm not getting any errors in my model. The simple fix can be adding

@@ -51,6 +51,7 @@ module Ambethia
       # variable +RECAPTCHA_PUBLIC_KEY+.
       def verify_recaptcha(options = {})
         return true if SKIP_VERIFY_ENV.include? ENV['RAILS_ENV']
+        model = options if options.is_a? ActiveRecord::Base
         private_key = options[:private_key] ||= ENV['RECAPTCHA_PRIVATE_KEY']
         raise ReCaptchaError, "No private key specified." unless private_key
         begin