2012-04-11 ago just one dedicated execution per document version -- NB: non-monotonicity of cancel always requires fresh update;
2012-04-09 ago simplified Future.cancel/cancel_group (again) -- running threads only;
2012-04-06 ago discontinued obsolete last_execs (cf. cd3ab7625519);
2012-04-06 ago discontinued Document.update_perspective side-entry (cf. 546adfa8a6fc) -- NB: re-assignment is always necessary due to non-monotonic cancel_execution;
2012-04-05 ago less aggressive discontinue_execution before document update, to avoid unstable execs that need to be re-assigned;
2012-03-15 ago some support for outer syntax keyword declarations within theory header;
2012-03-03 ago clarified terminology of raw protocol messages;
2012-01-05 ago tuned signature -- emphasize special nature of protocol commands;
2011-12-01 ago clarified modules (again) -- NB: both Document and Protocol are specific to this particular prover;