Bugfix: Methods on non-saved objects should return the correct value

This fixes method behaviors on non-saved objects.

Given:
```ruby
class User
  symbolize :color, :in => [:red, :blue], :default => :red
end
```

Before:
```ruby
@u = User.new

@u.color
=> :red

@u.red?
=> false
```

After:
```ruby
@u.red?
=> true
```