alts does receive "null" from channels

[ThomasDeutsch]

A channel, created with csp.go(function*().... will not yield and always return null in csp.alts.

var t = csp.go(function*() {
    while(true) {
      var action = yield csp.take(csp.timeout(2000));
      return "test"
    };
});

A channel like "t" will not work with alts. alts will not wait for a new value from t - it will receive "null" immediatly and it will run a loop that freezes the browser.