Trash: multiple properties

API 2.0.
Described 2 properties for `Trash`. The only last one is assigned. 

```ruby
class DateViewModel < Hashie::Trash
  property :month, from: :date, with: lambda { |date| raise date.month.inspect; date.month }
  property :year, from: :date, with: lambda { |date| date.strftime('%Y') }                                                                          
end

DateViewModel.new(date: Date.new) 
#=> <DateViewModel year="2012">
```
Only `:year` is assigned.
Expected `:month` to be assigned as well. 
Lambda for first property `:month` is not executed.