Add ``powerline-status`` to OS X installation documentation
Add ``powerline-status`` to OS X installation documentation

DoctorJellyface/powerline,bartvm/powerline,kenrachynski/powerline,cyrixhero/powerline,lukw00/powerline,IvanAli/powerline,S0lll0s/powerline,areteix/powerline,QuLogic/powerline,DoctorJellyface/powerline,bezhermoso/powerline,seanfisk/powerline,seanfisk/powerline,bezhermoso/powerline,russellb/powerline,seanfisk/powerline,dragon788/powerline,prvnkumar/powerline,EricSB/powerline,blindFS/powerline,russellb/powerline,blindFS/powerline,s0undt3ch/powerline,QuLogic/powerline,prvnkumar/powerline,EricSB/powerline,S0lll0s/powerline,Luffin/powerline,areteix/powerline,cyrixhero/powerline,dragon788/powerline,xfumihiro/powerline,junix/powerline,Liangjianghao/powerline,cyrixhero/powerline,bartvm/powerline,areteix/powerline,xfumihiro/powerline,Luffin/powerline,DoctorJellyface/powerline,russellb/powerline,Luffin/powerline,EricSB/powerline,IvanAli/powerline,xxxhycl2010/powerline,blindFS/powerline,s0undt3ch/powerline,junix/powerline,xfumihiro/powerline,darac/powerline,bezhermoso/powerline,kenrachynski/powerline,darac/powerline,prvnkumar/powerline,xxxhycl2010/powerline,Liangjianghao/powerline,kenrachynski/powerline,dragon788/powerline,S0lll0s/powerline,IvanAli/powerline,bartvm/powerline,lukw00/powerline,lukw00/powerline,Liangjianghao/powerline,darac/powerline,QuLogic/powerline,xxxhycl2010/powerline,junix/powerline,s0undt3ch/powerline