Gets the full path to the 'subdir/basename' file in the user binwalk directory.

        @subdir   - Subdirectory inside the user binwalk directory.
        @basename - File name inside the subdirectory.

        Returns the full path to the 'subdir/basename' file.

def _user_path(self, subdir, basename=''):
        '''
        Gets the full path to the 'subdir/basename' file in the user binwalk directory.

        @subdir   - Subdirectory inside the user binwalk directory.
        @basename - File name inside the subdirectory.

        Returns the full path to the 'subdir/basename' file.
        '''
        try:
            return self._file_path(os.path.join(self.user_dir, self.BINWALK_USER_DIR, subdir), basename)
        except KeyboardInterrupt as e:
            raise e
        except Exception:
            return None