Support for Execution monad

From a usability pov, if I'm going to be specifying args, wouldn't I generally want to write them first? i.e.
```
execute(Map(
  "foo" -> List("bar"),
  "anotherArg" -> List()
), for {
  // execution stuff here
} yield blahblah )
```
(I appreciate that in many cases there will be no extra args, but maybe you could have `execute` and `executeWithArgs`, or something like that.)