Do not represent scalar tags as 1-element tuples. Keep tag
type and count information in TiffTags.TAGS. Normalize data in
ImageFileDirectory.__setitem__: wrap and unwrap tuples as needed,
convert rationals to floats. (To ensure consistency, make the "tags"
attribute private.) Interpret byte data as a series of integers rather
than a bytearray (which should only map to the "undefined" type). On
Python3, if a str is assigned to an "undefined" tag, encode it as ASCII.
Note that a large number of tags have been removed from TiffTags.TAGS
because I do not have time to figure out the type and count of each of
them. They should be restored before this gets merged in.
This obviously breaks backwards compatibility in a lot of ways...
Fix for UnicodeDecodeError: ascii codec cannot decode byte while saving a TIFF image
Problem occured while saving TIFF images that contain non-ascii characters in metadata
Manually merged with master by wiredfool
