Supporting variable type for asset and amount

[ciricc]

Now numscript supports only monetary type for dynamic assets. But in some ways might need to use asset and amount independet. Like this, in one transaction.

vars (
  asset $asset
  number $amount
)

send [$asset $amount] (
  source = @world
  destination = @users:001
)

send [$asset *] (
  source = @users:001
  destination = @platform:profit
)