refactor demo task with new ProductNature nomencature
rename charges / products in expenses / revenues
update fixtures files
Merge branch 'master' of https://github.com/ekylibre/ekylibre

Conflicts:
	config/locales/arb/nomenclatures.yml
	config/locales/eng/nomenclatures.yml
	config/locales/fra/nomenclatures.yml
	config/locales/jpn/nomenclatures.yml
	config/locales/spa/nomenclatures.yml
	config/locales/statistics.yml
	config/nomenclatures/accounts.xml