Add GPSProcessingMethod tag to ExifInterface.

Change-Id: Ic5040daf33a921a5113e643f5729bc9e27f4f4c7
diff --git a/jhead.h b/jhead.h
index f12393b..60c2706 100644
--- a/jhead.h
+++ b/jhead.h
@@ -37,6 +37,7 @@
 #endif
 
 #define MAX_COMMENT_SIZE 2000
+#define GPS_PROCESSING_METHOD_LEN 100
 
 #ifdef _WIN32
     #define PATH_MAX _MAX_PATH
@@ -122,6 +123,7 @@
     // gps-datestamp is 11 bytes ascii in EXIF 2.2
     char GpsDateStamp[11];
     char GpsTimeStamp[11];
+    char GpsProcessingMethod[GPS_PROCESSING_METHOD_LEN + 1];
 }ImageInfo_t;