BugID: 725

Additions:
-Singleton methods in IViewPanel to make it possible to use only one panel for a specific treenode application
--Implemented these necessary changes in implementing classes.
-jParmDBnode is extended so the parmDB source is known for every treenode. It is therefore possible to mix data from various parmdb tables. Also a method is added to identify the node as a root node for a parmdb table.
Mods:
-Various small layout and plotter mods.