Async properties plus fromJS in TG

I implemented the async properties, now we have the defineAsyncProperty, the usage is 
https://github.com/Deividy/ezekiel/blob/f8b5b7593032fdfdeb0aa212e027cae6e47a41df/specs/activeRecords/event.coffee
https://github.com/Deividy/ezekiel/blob/f8b5b7593032fdfdeb0aa212e027cae6e47a41df/specs/access/async-properties.spec.coffee

I also made the fromJS, I implemented in doOne of TG, i think it's the most generic place to convert those values for now.

Please, let me know if i could do something better.
Thanks.