lua : modernize calling conventions to have more flexiblity
lua: allow sending lua commands via dbus

use org.darktable.service.Remote.Lua to send a lua string
lua: fix a typo in usermanual
dt_histogram_worker: fix memleak
Levels, exposure: better commit_params logic (in case of bad histogram)

Anything broken?
IOP Exposure: Deflicker: s/"thumbnail"/"pre-processed image"/
IOP Exposure: Deflicker: show mode switch only when dt_image_is_raw()
lua : return nil instead of NAN on latitude/longitude of images when not set
usermanual: several minor additions/corrections (plus xml source pretty-printing)
usermanual: update to the exposure module
lua usermanual : rework function synopsis to be more docbook friendly
usermanual: add missing hint in exposure module
Italian translation updated
Merge pull request #590 from bartokk/master

Italian translation updated
Merge branch 'master' of https://github.com/darktable-org/darktable
Translating in French and proof reading of the usermanual of dartable 1.5 till section 3.2.7 (not included) after an update made by 'make update-usermanual-fr'
	modified:   doc/usermanual/po/darktable-usermanual.pot
	modified:   doc/usermanual/po/fr.po