register_every_n_samples_event function doesn't work about pylibnidaqmx HOT 2 OPEN

Hello,

attached you will find a patch that fixes the problem. The drawback is that the 
task parameter now contains the task_handle (an integer) not the task object 
itself so you need to fix that in your AI_callback.py.

Maybe it would be a good idea to register a local callback that calls the 
callback given by the user, using the task object as parameter and maybe also a 
data array.
I also suggest to update the documentation as it was very confusing for me when 
I first tried to use this event. I can come up with a patch for that but I 
would like to know other opinions about the local callback part.

I guess that the done_event and signal_event have the same problem which can be 
fixed the same way, but I haven't tested this.

Best wishes,

Tobias

I 'fixed' this - although it is probably not fully thread-safe. The callback 
function now gets:
 * a Task object from the Task cache, so no new Tasks are created in the callback
 * the data retrieved from the DAQ card (instead of the number of samples).

It's a breaking API change, though, I guess. A more simple patch would not add 
the data as a parameter, which won't break the API.