Problem with datatable and a default preserveDataModel=true

[Mathias Brökelmann]

h:datatable now serializes the datamodel value during requests as a 
default setting. I think that this is quite problematic since every one 
who is using h:datatable without referring the special myfaces 
x:datatable must ensure that the values in the datamodel where serializable.

To minimize dependencies we are using h:datatable until we need some 
special functions of myfaces. But now we must refer to x:datatable just 
to disable the serialization of the datamodel.