Fix the scriptrunner to use consumer-producer model for scheduling scripts

Begin more exact: we want to use is a consumer-producer model. API calls like "run_script(accomID)" should add the acomID the the queue, while some separate thread would sleep until there are some new data in the queue, and process them by running related scripts.

I have managed it to get it to work using threads.
I run threads.deferToThread(scriptrunner_function) in the API __init__. I also create a threading.Condition(), and then use wait()/notify() to tell the scriptrunner_function that there are new scripts scheduled on the queue.

However, although it seems to work, I feel this is not the right approach. Twistd is all about getting rid of separate threads, and thus asynchronous code is recommended.