__del__ method simply calls the close() method
Refactor the way the read functions from the DNG class are used in the Tag class
Added more tags used with exif
Added suport for byte ascii and rational tag types
Store the order of the tags in the IFD for debugging purposes
Optional offset value when initializing a DNG allows to read the IFDs in the exif data of a jpeg file
get_images may fail at sorting images if they are not proper TIFF files
Raise an exception rather than stop the program if an invalid file is found. This is a library and shouldn't stop parent projects
New method read_jpeg_preview encapsulates the details of how to retrieve it