Add @nonobjc to topViewController in UIApplication extension to fix ld warning
Add @nonobjc to topViewController in UIApplication extension to fix ld warning

Without this linker emits following warning:
ld: warning: Some object files have incompatible Objective-C category definitions. Some category metadata may be lost. All files containing Objective-C categories should be built using the same compiler.

dongri/OAuthSwift,OAuthSwift/OAuthSwift,OAuthSwift/OAuthSwift,dongri/OAuthSwift