Task doesn't fire when changing concurrencey config between taskgroups and sub taskgroups.

[crito]

In the following example:

var group = new TaskGroup();

group.setConfig({concurrency: 1});

group.addTask(function () {
  console.log('Running first task outside of group.');
});

// Add a sub-group to our exiting group
group.addGroup(function(){
  // Tell this sub-group to execute in parallel (all at once) by setting its
  // concurrency to unlimited by default the concurrency for all groups is set
  // to 1 which means that they execute in serial fashion (one after the other,
  // instead of all at once)
  this.setConfig({concurrency: 0});

  // Add an asynchronous task that gives its result to the completion callback
  this.addTask(function(complete){
    setTimeout(function(){
      console.log('Running asynchronous task in group.')
    },500);
  });

  // Add a synchronous task that returns its result
  this.addTask(function(){
    console.log("Running synchronous task in group.")
  });
});

group.addTask(function () {
  console.log('Running second task outside of group.');
});

group.run()

I get the following result:

Running first task outside of group.
Running synchronous task in group.
Running asynchronous task in group.

The second task outside of the group is not fired. If I configure the concurrency of the task group to 0 instead of 1, it does fire as expected.

[balupton]

So the problem is actually a documentation problem!

  // Add an asynchronous task that gives its result to the completion callback
  this.addTask(function(complete){
    setTimeout(function(){
      console.log('Running asynchronous task in group.')
    },500);
  });

Doesn't call the completion callback! Therefore it hangs there.

I've created #7 for a possible way of detecting such problems.

[crito]

I added a note about this in the new usage docs I sent you with #9. But its still something that is really easy to overlook.