Add multi value

[Thomas Albertini]

Now that Luna supports subtractions and addition, should be able to call different functions like this

(module
  (func $subtractNumbers (param i32 i32) (result i32)
    local.get 1
    local.get 0
  	i32.sub
  )

  (func (export "addNumbers") (param i32 i32 i32) (result i32)
    local.get 0
    local.get 1
    call $subtractNumbers
    local.get 2
    i32.add))