2012-03-04 ago clarified special eol treatment and moved to gfx_range -- enables error messages at end of input, e.g. "prop PROP";
2012-03-03 ago retain original "uses" (again) -- still required for Thy_Load.use_file etc. in ML (notably for maintaining required/provided);
2012-03-01 ago Symbol.encode header edits;
2012-02-29 ago clarified module Thy_Load;
2012-02-26 ago include warning messages in node status;
2012-01-15 ago more precise rendering of overview_color/gutter_message/squiggly_underline based on cumulation of command status and warning/error messages;
2012-01-14 ago tuned comments;
2012-01-14 ago clarified partial restrict operation;
2012-01-09 ago command status color via regular markup;
2012-01-05 ago prefer raw_message for protocol implementation;
2011-12-01 ago clarified modules (again) -- NB: both Document and Protocol are specific to this particular prover;