[TIFF] EXIF tags may break reader

[n-lagomarsini]

When reading a TIFF Image with EXIF metadata using the TIFFImageReader, it is possible to find an exception. This exception happens when the EXIF IFD pointer tag has not the TIFF Tag type LONG(type = 4) but the IFD_POINTER type (type = 13). This new Tag type has been added in the Tech. Note 1 inside TIFF Specification Support and is not recognized by the reader. For this reason the EXIF IFD pointer doesn't load the EXIF IFD data but only the pointer associated. This lead to a ClassCastException when the TIFFImageReader tries to cast the EXIF IFD pointer data with the TIFFIFD class.