Add support for modifying a style.

Up to now it was only possible to modify the name, the description and
remove some iop from the style. It is now possible to add iop from
the selected image or to update it with the setting from the selected
image.
Minor code clean-up.
Use glong instead of long int for num in the gtk list store.

Indeed a G_TYPE_LONG corresponds to a glong which in turns corresponds
to a long int. But seems clearer to use glong as it emphasises the fact
that we are manipulating an item from a Gtk list store.
Added enable/disable for block_on_focus() and updated
all code using it to disable on gui_cleanup() this fixes
issues with focus-out event being handled for "dead" widgets.
Revert "Added enable/disable for block_on_focus() and updated"

This reverts commit d00d9f566442870d78b37ec5b91cffadaf59f002.
exif: fix a c++ compiler warning.
cli: fix crash in cleanup
noise profile: fix scripts to import presets for testing.
general: rewrite of previously reverted patch

with complete coverage this time and more intuitive naming scheme.
Fix compilation issue introduced in previous commit.
noise profile: canon powershot g12 by jb
noise profile: nikon d700 by jb
Adds iop guide style into darktableconfig.xml
Update french translation. Make it 100% translated.
rawspeed: Nikon 1 J3 support
rawspeed: Nikon 1 S1 support
adobe_coeffs: copy Nikon 1 V2 matrix for the J3
don't reset zoom when adding new instance
lens correction: fix for #9270

offer the three photometric GUI controls also when automatic search
gives more than one hit. Just take the first one as we already do
for process().
cache: have full buffers according to potentially exporting  threads