S9 LIB  (subvector vector integer1 integer2)  ==>  vector

SUBVECTOR returns a fresh vector formed from the members of VECTOR
beginning with index INTEGER1 (inclusive) and ending with index
INTEGER2 (exclusive).

(subvector '#(a b c d e) 2 4)  ==>  #(c d)
(subvector '#(a b c d e) 2 2)  ==>  #()
