fixed an NPE if the advancedsearch button doesn't exist.
Added logic to hide the delete button when a new entity is being
created.
Added logic to set the selection to the first item on the page if a
'new' operation is cancelled.
Added logic to select the first item in the table page after a delete.
removed references to 'contact' as this is a generic 'entity' table.
Added an extra check to see if the rowChangeListener is not null as is
some circumstances this is just used as a list.
removed the precondition as I actually use this class with out a field
group.
Added support for setting the whole fieldgroup to 'readonly'.