fix(README): Update to compile example against Rust beta
fix(README): Update to compile example against Rust beta

Remove unused import
res doesn't need to be mutable in parameter list
Change .listen() to string format
mfeckie/hyper,golddranks/hyper,sfackler/hyper,achanda/hyper,clatour/hyper,nstoddard/hyper,jmmaranan/hyper,ianks/hyper,nickgonzales/hyper,mlalic/hyper,mneumann/hyper,bonifaido/hyper,hannobraun/hyper,manuel-woelker/hyper,steveklabnik/hyper,lame-nickname/hyper,markuskobler/hyper,nstoddard/hyper,fengsp/hyper,nickgonzales/hyper,markuskobler/hyper,TimNN/hyper,youprofit/hyper,Keats/hyper,Twey/hyper,mikedilger/hyper,fuchsnj/hyper,Keats/hyper,peterhj/hyper,tempbottle/hyper,hannobraun/hyper,Twey/hyper,giftcards/hyper,hyperium/hyper,hannobraun/hyper,Twey/hyper,fhahn/hyper,tshepang/hyper,mre/hyper,Keats/hyper,tshepang/hyper,yazaddaruvala/hyper,yazaddaruvala/hyper,golddranks/hyper,hyperium/hyper,tshepang/hyper,bheesham/hyper,erickt/hyper,rschulman/hyper,hyperium/hyper,pyfisch/hyper,nickgonzales/hyper,mitsuhiko/hyper,markuskobler/hyper,reem/hyper,huonw/hyper,softprops/hyper,yangxingpping/hyper,golddranks/hyper,mlalic/hyper