added Library.undefined (in Scala);

more systematic treatment of internal state, which belongs strictly to the main actor, not the Swing thread;
do not re-use mutable DOM -- avoid races wrt. the rendering engine;
more thorough resize -- always recalculate metrics/margin synchronously;
asynchronous setDocument;
tuned;

component resize: full handle_resize;

adjusted to changes in Mapping.thy

merged

tuned

more lemmas about mappings, in particular keys

refined

nats in Haskell are readable

Let rsp and prs in fun_rel/fun_map format