use preferred resolver according to DOI Handbook §3.8

complete pattern coverage, e.g. relevant for singleton graph;

clarified iterations: enforce full top_down/bottom_up cycle for better stability of layout;

more explicit Layout.Info: size and content;
allow multi-line vertex label, based on content;
misc tuning;

tuned;

misc tuning;

configurable options;

proper level distance according to number of edges, as in old browser;

clarified Vertex.Ordering, to approximate situation before 4d985afc0565, which is relevant for level arrangement;

tuned;

rubberband method as in old browser;
tuned;

tuned;

tuned signature;

proper translate vertex (cf. 4d985afc0565);

explict layout graph structure, with dummies and coordinates;
explicit metrics for dummy box;
tuned signature;
misc tuning;

proper bounding box including dummies;

separate module Metrics;
maintain static metrics (with font) and visible_graph via layout;

more metrics, with integer coordinates for layout;
initial coordinates: center x as in old browser;
Layout.pendulum/collapse: proper downwards range;
distance as in old browser (see spaceBetween);
move offset as in old browser;
more careful comparison wrt. 0.0 (this is IEEE double, not int);

tuned;

misc tuning;

explicit Layout.Point;
tuned signature;
tuned;

tuned comments;

tuned;

tuned -- more iterators;

more formal Graph_Display.Node (with ordering) and Graph_Display.Edge;
misc tuning;
tuned signature;

tuned headers;

tuned signature;

--HG--
rename : src/Tools/Graphview/layout_pendulum.scala => src/Tools/Graphview/layout.scala