Harmonize TableWrapLayout2 and TableWrapData2 with Forms classes

Both the [TableWrapLayout2](https://github.com/eclipse-windowbuilder/windowbuilder/blob/master/org.eclipse.wb.rcp/src/org/eclipse/wb/internal/rcp/model/forms/layout/table/TableWrapLayout2.java) and [TableWrapData2](https://github.com/eclipse-windowbuilder/windowbuilder/blob/master/org.eclipse.wb.rcp/src/org/eclipse/wb/internal/rcp/model/forms/layout/table/TableWrapData2.java) are pretty old copies of the Forms classes which we have extended to store additional information during the layout.

We should separate the designer information from the layout algorithm to make sure that our implementation matches the actual implementation.