changed the javadocs for rules- and flavorText to only use negative type references.
changed CardSetIconFactory to also use Icon instead of raw SVGDocument
added mandate that the key property be sufficiently unique to base .equals() on
moved DefaultSymbolGroup to the core module and package
expanded SymbolIconFactory to include converting SymbolGroup to IconGroup "parallel" to Symbol to Icon conversions
 * removed Layout and FuseLayout interfaces, as they're implementation details
 * stripped Theme of a bunch of stuff thta is also implementation details
 * added FUSE as a LayoutType
 * added Card.getLayoutType() so each card can indicate how it's laid out
updated for new package of DefaultSymbolGroup
made fusing part of the Card model
removed layoutFused, as it's just another layout for a single card
added missing import of DefaultSymbolGroup, and addressed a couple warnings
made all the abstract methods non-abstract (but raising UnsupportedOperationException)
added ability to describe fuse cards in the descriptor
set up a fuse card and assertions for it's import, though the importer does not work currently
changed Icon.getSize() to return Dimension2D, instead of just Dimension, since icons are vector and can thus potentially have partial-pixel dimensions
started converting the text layout stuff to a new text-layout module and package based on BodyItem instead of Renderable.