Add new i18n languages and update existent ones

- Add 21 new languages where the UI was translated (all translations
  are 100% complete except for Chinese Simplified (96%)
  and Amharic (37%)).
- Update some translations for preexistent languages.

Change-Id: I64be0a2dd551c12af1547a616b4f49f97c471bde
diff --git a/src/_locales/nl/messages.json b/src/_locales/nl/messages.json
new file mode 100644
index 0000000..7b61d7d
--- /dev/null
+++ b/src/_locales/nl/messages.json
@@ -0,0 +1,114 @@
+{
+	"appName": {
+		"message": "Vertaal Geselecteerde Tekst",
+		"description": "The app name"
+	},
+	"appBetaName": {
+		"message": "Vertaal Geselecteerde Tekst (Beta)",
+		"description": "The beta app name"
+	},
+	"appDescription": {
+		"message": "Vertaal geselecteerde tekst met Google Translate",
+		"description": "The app description"
+	},
+	"contextmenu_title": {
+		"message": "Selectie vertalen naar...",
+		"description": "Title of the context menu that appears when a right click is done. Inside this parent menu there are the menus"
+	},
+	"contextmenu_title2": {
+		"message": "Selectie naar '$language$' vertalen",
+		"description": "Title of the context menu that appears when a right click is done and there's only one language available.",
+		"placeholders": {
+			"language": {
+				"content": "$1",
+				"example": "Language to translate into."
+			}
+		}
+	},
+	"contextmenu_edit": {
+		"message": "Talen bewerken...",
+		"description": "Title of the option inside the 'Translate section into...' context menu."
+	},
+	"options_welcome": {
+		"message": "Welkom!",
+		"description": "Title of the options page"
+	},
+	"options_introduction": {
+		"message": "Alstublieft, selecteer de talen die u wilt weergeven in het menu \"vertalen\".",
+		"description": "Introduction paragraph to the options pages"
+	},
+	"options_languageselectheader": {
+		"message": "Talen:",
+		"description": "Header of the language select option."
+	},
+	"options_otheroptionsheader": {
+		"message": "Andere opties:",
+		"description": "Header of the options page."
+	},
+	"options_tabsoption_1": {
+		"message": "Open Google Translate in een nieuw tabblad voor elke vertaling.",
+		"description": "Option which defines how should the app behave in relation to tabs."
+	},
+	"options_tabsoption_2": {
+		"message": "Open Google Translate in een enkel tabblad en vervang de nieuwste vertaling in plaats van het openen van meerdere tabbladen.",
+		"description": "Option which defines how should the app behave in relation to tabs."
+	},
+	"options_tabsoption_3": {
+		"message": "Open Google Translate in een paneel (U moet <a href='chrome://flags/#enable-panels' id='panelsflag'>--Panelen inschakelen</a> vlag activeren). <sup style='color:red; font-weight: bold;'> EXPERIMENTEEL</sup>",
+		"description": "Option which defines how should the app behave in relation to tabs."
+	},
+	"options_savebutton": {
+		"message": "Opslaan",
+		"description": "Save button in the settings page"
+	},
+	"options_addlanguage": {
+		"message": "Taal toevoegen",
+		"description": "Title for the 'Add language' dialog"
+	},
+	"options_addlanguage_addbutton": {
+		"message": "Toevoegen",
+		"description": "Add button in the footer of the languages list"
+	},
+	"options_language_label": {
+		"message": "Taal:",
+		"description": "Label for the language selector in the 'Add language' dialog"
+	},
+	"options_credits": {
+		"message": "Credits",
+		"description": "Title for the credits link and dialog"
+	},
+	"options_credits_homepage": {
+		"message": "startpagina",
+		"description": "Homepage link for an item in the credits. NOTE: put in in lowercase letters"
+	},
+	"options_credits_by": {
+		"message": "door",
+		"description": "Fragment of the author statement in an item of the credits. NOTE: put in in lowercase letters. EXAMPLE: '{{options_credits_by}} Adrià Vilanova Martínez'"
+	},
+	"options_ok": {
+		"message": "OK",
+		"description": "OK button in the dialogs"
+	},
+	"options_cancel": {
+		"message": "Annuleren",
+		"description": "Cancel button in the dialogs"
+	},
+	"notification_install_title": {
+		"message": "Bedankt voor het installeren van 'Vertaal Geselecteerde Tekst'"
+	},
+	"notification_install_message": {
+		"message": "Klik op deze melding om de extensie te configureren."
+	},
+	"notification_upgradedtostorage_title": {
+		"message": "'Vertaal Geselecteerde Tekst' werd bijgewerkt aan v0.6!"
+	},
+	"notification_upgradedtostorage_message": {
+		"message": "Uw instellingen worden nu gesynchroniseerd op al uw apparaten! Het enige slechte is dat u de extensie opnieuw moet installeren. :-( Klik op deze melding om te installeren."
+	},
+	"notification_reorder_title": {
+		"message": "'Vertaal Geselecteerde Tekst' werd bijgewerkt aan v0.7!"
+	},
+	"notification_reorder_message": {
+		"message": "Nu kunt u de volgorde configureren waarin u de talen wilt weergeven in het inhoudsmenu. "
+	}
+}