ex_impE was incorrectly listed as Safe

reflecting the changes made in HOLCF/ex and HOLCF/explicit_domains

added Classlib.* and Witness.*, moved (and updated) Coind.*, Dagstuhl.*, Dlist.*, Dnat.*, Focus_ex.* and Stream.* from HOLCF/explicit_domains to here adapted several proofs; now they work again. Hope that the following strange errors (when committing) do not matter: rlog error: RCS/Classlib.ML,v: No such file or directory rlog error: RCS/Classlib.thy,v: No such file or directory rlog error: RCS/Coind.ML,v: No such file or directory rlog error: RCS/Coind.thy,v: No such file or directory rlog error: RCS/Dagstuhl.ML,v: No such file or directory rlog error: RCS/Dagstuhl.thy,v: No such file or directory rlog error: RCS/Dlist.ML,v: No such file or directory rlog error: RCS/Dlist.thy,v: No such file or directory rlog error: RCS/Dnat.ML,v: No such file or directory rlog error: RCS/Dnat.thy,v: No such file or directory rlog error: RCS/Focus_ex.ML,v: No such file or directory rlog error: RCS/Focus_ex.thy,v: No such file or directory rlog error: RCS/Stream.ML,v: No such file or directory rlog error: RCS/Stream.thy,v: No such file or directory rlog error: RCS/Witness.ML,v: No such file or directory rlog error: RCS/Witness.thy,v: No such file or directory

moved Coind.*, Dagstuhl.*, Focus_ex.* to HOLCF/ex, marked the remaining files as obsolete (new versions in HOLCF/ex)

added def_fix_ind and def_wfix_ind for convenience

added addloop (and also documentation of addsolver