Function IsUTF8Continuation

3rdparty/tinyxml2/tinyxml2.h:605–607

    }

    inline static bool IsUTF8Continuation( const char p ) {
        return ( p & 0x80 ) != 0;
    }

    static const char* ReadBOM( const char* p, bool* hasBOM );
    // p is the starting location,