Add DateTimeOriginal to easyaccess

include/exiv2/easyaccess.hpp

@@ -42,6 +42,8 @@ namespace Exiv2 {
     EXIV2API ExifData::const_iterator orientation(const ExifData& ed);
     //! Return the ISO speed used to shoot the image
     EXIV2API ExifData::const_iterator isoSpeed(const ExifData& ed);
+    //! Return the date and time when the original image data was generated
+    EXIV2API ExifData::const_iterator dateTimeOriginal(const ExifData& ed);
     //! Return the flash bias value
     EXIV2API ExifData::const_iterator flashBias(const ExifData& ed);
     //! Return the exposure mode setting

src/easyaccess.cpp

@@ -183,6 +183,15 @@ namespace Exiv2 {
         return md;
     }
 
+    ExifData::const_iterator dateTimeOriginal(const ExifData& ed)
+    {
+        static const char* keys[] = {
+            "Exif.Photo.DateTimeOriginal"
+            "Exif.Image.DateTimeOriginal"
+        };
+        return findMetadatum(ed, keys, EXV_COUNTOF(keys));
+    }
+
     ExifData::const_iterator flashBias(const ExifData& ed)
     {
         static const char* keys[] = {