First iteration of settings screen
Added back button
More logical position
Added settings object
Updated settings (+ fix doc)
Use of settings in Camera
Changed the way Home.screen works (step 1)
Draft for new Home.screen and items

The idea is to generalize the items used and drawn
in the main and setting screens.
I want them to be more generic and eventually (don't worry
@Vlanvin) to merge them them with BaseMixins.
I will later implement classes for easy setting manipulation.
We want modal < actionnable < item
First implementation of future item and actionnable
Merge branch 'master' into settings

Conflicts:
	src/interface/Camera.ml
New interface for home screen
Added modal item
has_focus is now protected (and in the mli)
First test on settings menu
Right back_hover image
Added parameters (less hardcode)
Sliders are now well rendered
Modified rendering of text
Now setter is modal