handlePanelScroller, rodButtonPanelScroller, viewpanelContainerScroller,
bodyPanelScroller (in StructureView); 
rootScreen,centerPanel renamed to rootPanel,mainPanel
introduced a domain of category names
Claims extends Entity (not Form); introduced Arrow
introduced Form Constants and some basic Arrows:
NullArrows always return NULL_RESULT;
JavaArrow<T> acts on any Java Object of type T
jmorph() may return any Java Object
morph() must return a Structure
created the first non-trival Arrow: a factory that transforms a String
into a StringCategory, stored as a static member of StringCategory
simplified the JavaArrow interface by moving the jmorph() method,
which returns an object, into the separate interface JavaArrowWeak