Fix bug in SHORTEST-PATH

Also correct typo in initarg :END-NODE of NO-PATH-CONDITION.`
Work around missing arglist info in ECL

* Provide DEFUN* macro that is similar to DEFUN but creates a
  funcallable instance that stores its lambda list.
* Define funcallable class ALISP-FUNCTION for the result of DEFUN*.
* Depend on Closer MOP so that ALISP-FUNCTION can be defined in a
  portable manner.