[Kde-imaging] DNG converter & active area

[Jens Müller]

In opposite to adobes dng converter the kipi dng converter store not the whole 
sensor image to the dng file but only the active sensor area. This is due 
missing options in libkdcraw's interface while internal libraw providing these 
options. As there are already some libkdcraw API changes I will add these 
options to libkdcraw interface first. For support in kipi dngconverter there 
are some issues with some NEF files, so I check them before merging to 
dngconverter.

There is also a page providing some more information on dng: 
http://www.barrypearson.co.uk/articles/dng/specification.htm

Regards, Jens