capitalize more carefully, e.g. relevant for option "ML_exception_trace";
unused;
proper tooltip_lines for multi-line text;
tuned;
tuned option name;
tuned;
tuned comments;
added protocol command "use_theories", with core functionality of batch build;
reintroduced process interrupt for the sake of synchronous protocol commands like "use_theories" (see also 27930cf6f0f7);