added test for redtube.com 

I just added the test for redtube.com
added redtube.com in InfoExtractors (2nd pull request with the required amindments)

added redtube.com in InfoExtractors (2nd pull request with the required amindments). Now this script can also download redtube.com videos
Redtube test now works

I just did a little makeover by changing redtube tests. Now they are passed.
Moved redtube info extractor to the end
Simplify RedTube