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.

rtengine/dcp.cc

@@ -696,7 +696,8 @@ DCPProfile::DCPProfile(const Glib::ustring& filename) :
         return;
     }
 
-    std::unique_ptr<TagDirectory> tagDir(ExifManager::parseTIFF(file, false));
+    ExifManager exifManager(file, nullptr, true);
+    std::unique_ptr<TagDirectory> tagDir(exifManager.parseTIFF(false));
 
     Tag* tag = tagDir->getTag(toUnderlying(TagKey::CALIBRATION_ILLUMINANT_1));
     light_source_1 =