Add --recursive to the git clone instructions in the README
Add --recursive to the git clone instructions in the README

`rake setup` will handle this anyway; this is mainly just an attempt
to teach folks that the --recursive option is there :)

SuPair/cheddar-ios,jianwoo/cheddar-ios,yzpniceboy/cheddar-ios,nothingmagical/cheddar-ios,jianwoo/cheddar-ios,SuPair/cheddar-ios,liduanw/cheddar-ios,iOSTestApps/cheddar-ios,yzpniceboy/cheddar-ios,iOSTestApps/cheddar-ios,liduanw/cheddar-ios