changed order of lemmas to overwrite the general code equation with the nbe-specific one

adapt proofs to changed set_plus_image (cf. ee8d0548c148);

bash wrapper: terminate only in exceptional case, keep background processes running (e.g. 'thy_deps' or 'display_drafts');

updated latex dependencies (cf. 7d88ebdce380);

tuned README;

isabellesym.sty: eliminated dependency on latin1, to allow documents using utf8 instead;

proper theory name (cf. e84f82418e09);

merged;