Add SkipFlagParsing to app

testdata/godoc-v2.x.txt

@@ -327,6 +327,8 @@ type App struct {
 	// Allows global flags set by libraries which use flag.XXXVar(...) directly
 	// to be parsed through this library
 	AllowExtFlags bool
+	// Treat all flags as normal arguments if true
+	SkipFlagParsing bool
 
 	// Has unexported fields.
 }