Merge branch 'Threads'

Conflicts:
	Crawler/Crawler.cs
	Crawler/WebPage.cs
Merge branch 'master' of https://github.com/thilemann/WebCrawler
Merge branch 'master' of https://github.com/thilemann/WebCrawler
Removed time from the output path pattern
Changed the signature of LoadFileMap. It now returns a Dictionary with the files. This was Nessesarry when we are using the Indexer without crawling new pages first. Furthermore the timestamp was removed from the output path. Also the seperator between uri and file name was changed due to uris containing ;.
Added a try catch around the Parallel.ForEach statement since it threw an exception
Implemented stop words - This was done by having a static array containing all english stopwords. Then in the Tokenizer.Tokenize method we returl all tokens retrieved from the page, except those which are in the array.