Async livenet

[zie1ony]

We would like to speed up the livenet executions. This means two main cases:

• concurrent deploys - this could be done via hidden threading
• concurrent getters

async! { env,
    let approved = self.name_token.get_approved(token_id, token_hash);
    let owner = self.name_token.owner_of(token_id, token_hash);
};