Added an extention to the filter method

[hileamlakB]

In this module a Proxyfilter class is defined with more methods that doesn't quit fit in the filter function of the Collector class like - Methods for filtering ip's with unique country - Methods to determine working proxies - More will be added in the future ......

BTW, these is a great liberary, Thanks. I was going to those free proxy sites to make my own scrapper when I found these it save me a ton.

And even tho I am not that good yet, I have added some functionalities that I wanted, so here they are. If you have time, look at it and tell me what to fix. And no hurt feelings if you can't make the time or if my code is rubbish.