Add multi-frame handling.

- Exif of all frames are displayed in the Editor's Exif tab (without
separator)
- isHDR and isPixelShift is added to the data files stored in cache
- In the Editor panel, the QuickInfo frame display the HDR and
PixelShift information, as well as the number of frame and bit-depth for
HDR image
- the number of frame is provided by dcraw. If not set, it is provided
by the Exif's main IFD count
- the PixelShift information (for Pentax as of now) is provided by
looking at the Exif informations
- the HDR information is provided by the Exif information of the first
frame for Pentax raw files, or by the bitspersample, sampleformat and
compression tags for other files

TODO: add icons to the thumbnails to tag HDR and PixelShift files.

rtgui/iptcpanel.h

@@ -75,7 +75,7 @@ public:
     void write          (rtengine::procparams::ProcParams* pp, ParamsEdited* pedited = nullptr);
     void setDefaults    (const rtengine::procparams::ProcParams* defParams, const ParamsEdited* pedited = nullptr);
 
-    void setImageData   (const rtengine::ImageMetaData* id);
+    void setImageData   (const rtengine::FramesMetaData* id);
 
     void notifyListener ();