Update swift usage instructions
Update swift usage instructions

CocoaLumberjack/CocoaLumberjack,sushichop/CocoaLumberjack,jum/CocoaLumberjack,DD-P/CocoaLumberjack,CocoaLumberjack/CocoaLumberjack,DD-P/CocoaLumberjack,sushichop/CocoaLumberjack,jum/CocoaLumberjack,sushichop/CocoaLumberjack,sushichop/CocoaLumberjack,jum/CocoaLumberjack,DD-P/CocoaLumberjack,CocoaLumberjack/CocoaLumberjack,CocoaLumberjack/CocoaLumberjack,jum/CocoaLumberjack