fix i18n key
small i18n fixes and clarifications
small translation updates
small invoice i18n cleanup/refactoring
Merge branch 'master' into selfsignup
Merge branch 'selfsignup' into onlinepay
Merge branch 'master' into uicleanup

Conflicts:
	config/locales/nl.yml
Merge branch 'uicleanup' into foodcoop-adam-new
Merge branch 'onlinepay' into foodcoop-adam-new