The main change in this version: proper Show, Read and Eq instances
for both graph implementations. Previously, Data.Graph.Inductive.Tree
had a pretty-printed Show output; now both it and PatriciaTree have
Show and Read instances via the mkGraph function, and Eq via deriving
(I'm not sure how well this will work because as I write this I
realise it may not deal with multiple edges that well... I guess I'll
be doing an updated version tomorrow after getting some sleep ;p).
The previous Show behaviour of Tree is now available as a
pretty-printing function for all DynGraph instances.
The PatriciaTree implementation is now exported and used by default,
because as far as I'm aware it will always perform better.
Finally, the Data.Graph.Inductive.Graphviz module has been removed; if
you want to visualise your fgl graph, please see my graphviz package
on Hackage (cheap plug? moi?).