clarified signature: Known.theories retains Document.Node.Entry (with header);

tuned signature;

clarified signature;

tuned signature;

clarifified selection: always wrt. build_graph structure;
tuned signature;

tuned signature;

clarified signature;

clarified signature: global_theories is always required;

tuned;

more informative Imports.Report with actual session imports (minimized);

clarified signature;

theory qualifier is always session name (see also 31e8a86971a8);

clarified modules;

option -B for "isabelle build" and "isabelle imports";

tuned signature;

tuned signature;

more documentation;
tuned message;

clarified signature: provide all_known information uniformly (it is subject to Sessions.T selection);

clarified errors;

support for incremental update according to session graph structure;

clarified platform file operations;

clarified output;

update strictly local imports only;

proper imports_base;

tuned;

clarified import of loaded theory;

tuned signature;

prefer explicit progress channel;

clarified: repository files before commit;

support for potential session imports;

tuned messages;

support for Mercurial manifest check;

support for multiple operations via options;

clarified tool name -- more official status;

--HG--
rename : src/Pure/Tools/update_imports.scala => src/Pure/Tools/imports.scala