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/dynamicprofilepanel.cc

@@ -405,7 +405,7 @@ void DynamicProfilePanel::render_fnumber (
     RENDER_RANGE_ (double, fnumber,
     [] (double f) {
         return std::string ("f/") +
-               rtengine::ImageMetaData::apertureToString (f);
+               rtengine::FramesMetaData::apertureToString (f);
     });
 }
 
@@ -421,7 +421,7 @@ void DynamicProfilePanel::render_shutterspeed (
     Gtk::CellRenderer *cell, const Gtk::TreeModel::iterator &iter)
 {
     RENDER_RANGE_ (double, shutterspeed,
-                   rtengine::ImageMetaData::shutterToString);
+                   rtengine::FramesMetaData::shutterToString);
 }