fixed arg casting

Author: radutopala

options.go

@@ -73,17 +73,17 @@ func (arg Argument) Explain() string {
 
 // String casts a value to a string and panics on failure.
 func (arg Argument) String() string {
-	return *arg.Value.(*string)
+	return arg.Value.(string)
 }
 
 // Bool casts a value to a bool and panics on failure.
 func (arg Argument) Bool() bool {
-	return *arg.Value.(*bool)
+	return arg.Value.(bool)
 }
 
 // Int casts a value to an int and panics on failure.
 func (arg Argument) Int() int {
-	return *arg.Value.(*int)
+	return arg.Value.(int)
 }
 
 type sortArguments []*Argument