Add vector-fold{-right}, remove string-{any|every}

[gambiteer]

The definitions of string-any and string-every in SRFI 13 are not parallel to the definitions of vector-any and vector-every in SRFI 133. So move the definitions of vect-any and vect-every in _std#.scm from a block executed both for vectors and strings to a block executed just for vectors. Put definitions of vect-fold and vect-fold-right in a block that is executed only for vectors, not strings.

string-any and string-every are still available in SRFI 13.