Enable autogrow function on bean wrapping

A datasource can have a field of type list:object. With such a datasource I can create an action which offers the possibility to post values to be bound on object-attributes of objects within that list.

To be able to handle such a post request in appNG, the bind class must have as much instantiated objects within the list as needed to bind the object-attribut-values at the time when the post parameters gets bind to the bind class.

At the moment, this can only be done if the list gets pre-filled with some objects on instantiation of the bind class. A better solution would be to enable the autogrow feature of the used BeanWrapperImpl.

The enabling of that function shall be optional and it shall be possible to enable it distinct per bind class or bind class usage.