function chain(subject) {
    return new ChainWrapper(subject, true);
  }
Creates a chain object that wraps `subject`, enabling <i>explicit</i> chain sequences. <br/>
Use `v.prototype.value()` to unwrap the result.

@memberOf Chain
@since 1.0.0
@function chain
@param  {string} subject The string to wrap.
@return {Object}         Returns the new wrapper object.
@example
v
 .chain('Back to School')
 .lowerCase()
 .words()
 .value()
// => ['back', 'to', 'school']