Updated xeth instances to take extra param for ui.Interface

Please be aware that if any of the instances on xeth.frontend are called
the program will crash due to the default, temporarily, frontend
interface.

cmd/ethereum/js.go

@@ -46,7 +46,7 @@ func execJsFile(ethereum *eth.Ethereum, filename string) {
 	if err != nil {
 		utils.Fatalf("%v", err)
 	}
-	re := javascript.NewJSRE(xeth.New(ethereum))
+	re := javascript.NewJSRE(xeth.New(ethereum, nil))
 	if _, err := re.Run(string(content)); err != nil {
 		utils.Fatalf("Javascript Error: %v", err)
 	}
@@ -61,7 +61,7 @@ type repl struct {
 }
 
 func runREPL(ethereum *eth.Ethereum) {
-	xeth := xeth.New(ethereum)
+	xeth := xeth.New(ethereum, nil)
 	repl := &repl{
 		re:       javascript.NewJSRE(xeth),
 		xeth:     xeth,