* Alter `format-symbol` to accept a string designator as the format
  control.
* Use uninterned symbols as format control for type names in type.lisp
  to get the correct names in case-sensitive lisps.

  Add bunch of missing symbols to the manual, and go over several
  docstrings reformatting them for the benefit of the documentation
  generator.

  (A crapton of symbols are still not in the manual.)

 * plus a test-case

Added:
 * XOR
 * WHICHEVER
 * SWITCH, ESWITCH, CSWItCH
 * UNIONF, NUNIONF
 * ALIST-PLIST, PLIST-ALIST
 * ENSURE-CONS
 * NAMED-LAMDBA
 * DEFINE-CONSTANT
 * STRING-DESIGNATOR

Note:
 Documentation strings of many new operators are sorely lacking, particularly
 NAMED-LAMBDA and *SWITCH.