Add syntactic sugar for multiple assignment in audited let.
Add syntactic sugar for multiple assignment in audited let.

`
let! x:int=!3,
     y:int=!4,
in <x>
`
is equivalent to:

`let! x:int=!3 in
   let! y:int=!4 in
     <x>
 `

jgardella/AuditedComputation