Ignore any arguments that are None.
Ignore any arguments that are None.

Fixes issues #33

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