added delcongs, Delcongs, unsafe_solver, safe_solver, HOL_basic_ss,
safe_asm_more_full_simp_ta, clasimpset HOL_css with modification functions
new addss (old version retained as unsafe_addss),
new Addss (old version retained as Unsafe_Addss),
new auto_tac (old version retained as unsafe_auto_tac),
Inductive = Gfp + Prod + Sum + "indrule"