add real deletion of polytomouskeynodes
updated node number to the one from the parent (#2892)
PolytomousKeyListEditor.java : changed table view for polytomous key nodes added edges column to make it more clear.
PolytomousKeyListLabelProvider.java : added labels for edges and updated node number function
RefreshNodeNumberingOperation.java : calls the refreshing node function in PolytomousKeyNode
had to rename the packages to make them compliant with buckminster