Image Reader suggestions for improvement

1. True support for 16 bits TIFF images. The current image reader of
Qt supports 16 bits TIFF images, but it truncates 16 bits images to 8
bits images, which leads to loss of quality.

2. Support for RAW image formats. This shouls be possible by accessing
Cocoa in Mac and WIC in Windows (Windows Imaging Components). The
current image reader cannot read any RAW image formats.

3. Support for EXIF information. At least the most common tags should
be supported. The current image reader is not able to read EXIF
information at all.

P.S. We have also another proposal that would be much easier to
implement:

4. The integration of dcraw, which very widely used to decode RAW
images. dcraw would enable RAW support for all platforms!