Modified some french translations to mirror the english ones.
Added additional needed line, clarified variable

Conflicts:
	doc/guides/2 - Refinery Basics/4 - Extending Controllers with Decorators.textile
Fixes #2539 by checking if extension was specifically supplied as an option.
Remove redundant translations from core locales.
Remove redundant and fix existing translations in authentication locales.
Move one of the ru dashboard translation under proper section.

Conflicts:
	dashboard/config/locales/ru.yml
Remove redundant and fix existing it images translations.

Conflicts:
	images/config/locales/it.yml
Remove redundant and fix existing resource translations.

Conflicts:
	resources/config/locales/it.yml