Non-string exif tags (e.g. GPSLatitude and GPSLongitude) have zero value

This commit calls utf8_encode on all exif tags after reading: http://drupal.org/cvs?commit=433564

However, some exif tags are arrays, for example the GPS latitude and longitude tags. These values are lost.

Attached patch runs utf8_encode() on all non-array tags. Not sure if there are any array tags that need to be utf-8 encoded.