Made s.map(Object) use original value when key/value are the same, for convenience.  Also made the delimiters for s.map [] instead of {{}}.
Added s.forEach, e.set, and s.set which calls e.set.  s.forEach is mainly for chaining, and the e/s.set is for extending (which they do not yet do).
Made s.get default to s.get(0).