Async: Don't use testFunc.toString to guess argument names or count

[mcbain]

http://stackoverflow.com/questions/1007981/how-to-get-function-parameter-names-values-dynamically-from-javascript

These technique does not work when using code-minification ( --production flag) or a function-wrapper without (test,waitFor) args in source-code.

Please allow to flag a test to be 'async' e.g

      it.async = function (name, fn) {
       it(name, function (test, waitFor) {
        return fn.apply(this, arguments);
    });
      };

[rbabayoff]

OK, will take a look at it when we're back form vacation.