Question: Grammar change to allow `,` in type annotations

I couldn't find any issue regarding this, but the following works now: 

``` ts
var foo: {a:any,b:any} // notice the `,` 
```

Was this change intentional. Should I consider it stable?

I see that the team still uses `;` e.g. check the interface members in https://github.com/Microsoft/TypeScript/blob/master/src/compiler/types.ts :rose:
