Akshell modules - add to exports, don't replace it

gistfile1.js

repr([1, 2, 3, 4].map(function(i) { return require('./testrequire' + i).foo; }))
["bar", undefined, undefined, "bar"]

testrequire1.js

exports.foo = "bar";

testrequire2.js

module.exports = {foo: "bar"};

testrequire3.js

exports = {foo: "bar"};

testrequire4.js

function extend(d, s) {
  for (p in s) {
    if (s.hasOwnProperty(p)) {
      d[p] = s[p];
    }
  }
}

extend(exports, {foo: "bar"});