Add QMessageBox::information() support to host environment

src/typica.w

 @<Function prototypes for scripting@>=
 QScriptValue displayWarning(QScriptContext *context, QScriptEngine *engine);
 QScriptValue displayError(QScriptContext *context, QScriptEngine *engine);
+QScriptValue displayInfo(QScriptContext *context, QScriptEngine *engine);
 
 @ This function is exposed to the host environment.
 
 engine->globalObject().setProperty("displayWarning", constructor);
 constructor = engine->newFunction(displayError);
 engine->globalObject().setProperty("displayError", constructor);
+constructor = engine->newFunction(displayInfo);
+engine->globalObject().setProperty("displayInfo", constructor);
 
 @ The function takes some arguments.
 
     return QScriptValue();
 }
 
+QScriptValue displayInfo(QScriptContext *context, QScriptEngine *)
+{
+    QMessageBox::information(NULL, argument<QString>(0, context),
+                             argument<QString>(1, context));
+    return QScriptValue();
+}
+
 @* Scripting QMainWindow.
 
 \noindent Rather than directly exposing |QMainWindow| to the scripting engine,