Extended %variable-cache-ref, %safe-variable-cacahe-ref and

Extended %variable-cache-ref, %safe-variable-cacahe-ref and
%variable-cache-set with an additional 'IGNORE-TRAPS? field.  This
field is always a quotes constant.  When True it causes reference or
assignment traps to be ignored.

Added code to attach declarartions IGNORE-REFERENCE-TRAPS and
IGNORE-ASSIGNMENT-TRAPS to the environment frame for the block in
which they occur.

TO DO: (1) include reference environment in captures (2) use this to
determine whether or not the reference has an IGNORE-* declaration and
fill in the %variable-cache-ref (etc) slots.