Initial code stub for generating the preference panel
for session import options.
Initial implementation stub of import session
More implementation for import session.
Remove all import storage configuration now when they are avail
in preference panel.
Make use of a import session instance in camera jobs.
Move logics for evaluating a new filename if exists into import session
from the camera import job.
Initial clean up  of capture view and added use of import session.
Merge remote-tracking branch 'upstream/master' into session
Refactor tethering to use new session import per capture job
to detach it from the view itself.

- Rewrote camera jobs to use a session import.
- Make use of the new camera job in camera.c
- Removed duplicated code and clean up of the tethering view
Fix shared camera settings.
lua : document email exporter

forgoten in the 1.4 doc, sorry about that
lua : remove default handler for types

this functionnality was unused and tricky to maintain
lua : implement proper inheritence in lua

this allows to properly handle c structs that extend other C struct
add -dev suffix to lua API version
Check if we got a pattern in import session.
Wait for all captures to be downloaded before exiting capture job.
Add a button to cycle through rating comparators

The list is <, <=, =, >=, >, !=
tonecurve revamped

we no longer clamp the a and b channel when using the corresponding curves.
instead an extrapolation is applied at both sides of the curve. this fixes
possible hue banding and artifacts mainly for images with certain highly saturated
colors (think of blue illuminated buildings at night, stage photos etc.)

as usual existing history stacks are kept untouched - if you want to take
advantage of the improvements for those you need to reset the tonecurve module.
colorcontrast revamped

same as before: no clamping of a and b channels.
Use a mutex/cond for capture job to prevent job finish
before all camctl image download events have been processed.