gapi: Bring back puppet and langpuppet

This reverts commit e767655ede.

In addition, it applies required changes to function with the new CLI backend.

lib/main.go

@@ -761,7 +761,7 @@ func (obj *Main) Run() error {
 			}
 			var timing time.Time
 
-			// make the graph from yaml, lib, or dsl!
+			// make the graph from yaml, lib, puppet->yaml, or dsl!
 			timing = time.Now()
 			newGraph, err := gapiImpl.Graph() // generate graph!
 			if err != nil {