Added support for "ellipse" node shape
Removed 'phantom edges' from undirected graphs
Added agopenSized() function to create Ragraph objects whose size is determined by graphviz
agopenSized also passes edge weight information through properly, resulting in nicer looking graphs
Added graphWidth and graphHeight functions to get graph dimension details easily for plotting
Plot Ragraph objects at their specified size rather than fitting to the graphics device
Added support for triangle, pentagon, hexagon, septagon, octagon, diamond and square node shapes
Added support for edge labels
Added support for dot/odot and box/obox arrow types
Arrow length for "open" and "closed" arrows set to graphviz default, now handles arrowsize better
Improved naming of grobs
Named the graph viewports
Handle node 'col' or 'fill' of ""
Handle arrowsize more sensibly
Support for arrowhead="dot"
New argument 'nodesOnTop' for grid.graph() so that user can control whether nodes or edges are drawn last (on top).