Add test for Stream.filter().
Add test for Stream.filter().

svven/tweepy,tsablic/tweepy,abhishekgahlot/tweepy,LikeABird/tweepy,kcompher/tweepy,nickmalleson/tweepy,vikasgorur/tweepy,ze-phyr-us/tweepy,IsaacHaze/tweepy,nickmalleson/tweepy,ze-phyr-us/tweepy,arunxarun/tweepy,vivek8943/tweepy,markunsworth/tweepy,sidewire/tweepy,obskyr/tweepy,takeshineshiro/tweepy,aleczadikian/tweepy,hackebrot/tweepy,edsu/tweepy,robbiewoods05/tweepy,cinemapub/bright-response,awangga/tweepy,thelostscientist/tweepy,damchilly/tweepy,bconnelly/tweepy,sa8/tweepy,yared-bezum/tweepy,truekonrads/tweepy,rudraksh125/tweepy,raymondethan/tweepy,wjt/tweepy,conversocial/tweepy,aganzha/tweepy,cogniteev/tweepy,techieshark/tweepy,iamjakob/tweepy,nickmalleson/tweepy,kylemanna/tweepy,Choko256/tweepy,tuxos/tweepy,elijah513/tweepy,kskk02/tweepy,srimanthd/tweepy,nickmalleson/tweepy,markunsworth/tweepy,cinemapub/bright-response,vishnugonela/tweepy,tweepy/tweepy,zhenv5/tweepy,abhishekgahlot/tweepy,atomicjets/tweepy