'Abstraction of a threadpool. A newspool can accept any number of
source OR article objects together in a list. It allocates one
thread to every source and then joins.
We allocate one thread per source to avoid rate limiting.
5 sources = 5 threads, one per source.
>>> import newspaper
>>> from newspaper import news_pool
>>> cnn_paper = newspaper.build(\'http://cnn.com\')
>>> tc_paper = newspaper.build(\'http://techcrunch.com\')
>>> espn_paper = newspaper.build(\'http://espn.com\')
>>> papers = [cnn_paper, tc_paper, espn_paper]
>>> news_pool.set(papers)
>>> news_pool.join()
# All of your papers should have their articles html all populated now.
>>> cnn_paper.articles[50].html
u\'<html>blahblah ... \''

def __init__(self, config=None):

    self.papers = []
    self.pool = None
    self.config = (config or Configuration())
