Log Message:
Update to 0.17.

Significant Changes from version 0.16

* Exiv2 utility
	-          [tools] exiv2 now writes a proper XMP sidecar file (it used to
	           just dump the XMP packet to a file).
	-          [tools] exiv2 can now also save Exif and IPTC data in the XMP
	           sidecar file (conversion of Exif/IPTC to/from XMP).

* Exiv2 library
	- 0000546: [exif] Exiv2 crashes while converting Nikon lens information
	           for pretty printing.