New Debugging Features:

Search-stack:
(:s "cal") or (:s 'cal) searches the stack for a frame whose function or 
special form has a name containing "cal", moves there to display the local
data.

Break-locals:
:bl displays the args and locals of the current function.
(:bl 4) does this for 4 functions.

(si:loc i)  accesses the local(i): slot.
the *print-level* and *print-depth* are bound to si::*debug-print-level*

Recall that kcl permits movement to previous frame (:p) and next frame (:n).
These also take numeric args eg. (:p 7) moves up 7 frames.

If functions are interpreted, the arg values are displayed together
with their names.  If the functions are using the C stack (ie proclaimed 
functions), very little information is available.


Note you must have space < 3  in your optimize proclamation, in order for
the local variable names to be saved by the compiler.

To Do: add setf method for si:loc.
add restart capability from various spots on the stack.