Configuration fixes: default values, merging logo-icon and logo-image options.
Fixed: crash if 'background' option is missing in .conf
Functions/signales/widgets renaming, checking contrast theme availability
Functions/signales/widgets renaming, checking contrast theme availability, font-scale replace font-increment.
Merge branch 'dev_font_scale' into develop

Conflicts:
	data/lightdm-another-gtk-greeter.conf
	src/configuration.c
	src/indicator_a11y.c
	src/main.c
	src/shares.h
Small fixes
Version improved