Thm_cont.EVERY

When given a list of theorem-tacticals and a theorem, EVERY_TCL simply composes their effects on the theorem. The effect is:

   EVERY_TCL [ttl1;...;ttln] = ttl1 THEN_TCL ... THEN_TCL ttln

In other words, if:

   ttl1 ttac th1 = ttac th2  ...  ttln ttac thn = ttac thn'

then:

   EVERY_TCL [ttl1;...;ttln] ttac th1 = ttac thn'

If the theorem-tactical list is empty, the resulting theorem-tactical behaves in the same way as ALL_THEN, the identity theorem-tactical.