Enable setting of programmatic column name in NotesViewColumn class

Currently the ItemName property is read only. As the CopyColumn method in NotesView class is always copying the itemName to the target view this creates multiple columns with the same programmatic name if you copy a column serveral times.

With this restriction it is not possible to use a view with some default columns as template for other views with a dynamic amount of these colmuns.

In general it would be very helpful to be able to change all properties of NotesViewColumn class. This would enable to design really nice views programmatically, e.g. as output for QueryREsultsProcessor.