bundlerefication.
Fix integration with ActiveRecord [closes #2, closes #26].

attr_encrypted methods assumes that all attribute methods already defined
when it calls instance_methods, but there are cases when that is not true,
because ActiveRecord defines that methods dynamically (in method_missing and
respond_to?).

See lib/active_record/attribute_methods.rb for details.
Merge remote-tracking branch 'origin/issue-2-ruby19-compatibility'