Добавлен обработчик NotFound

Исправлена опечатка в тесте
Разделена логика метода BuildNonElyTexturesHash

lib/routes/NotFound.go

@@ -0,0 +1,18 @@
+package routes
+
+import (
+	"net/http"
+	"encoding/json"
+)
+
+func NotFound(w http.ResponseWriter, r *http.Request)  {
+	json, _ := json.Marshal(map[string]string{
+		"status": "404",
+		"message": "Not Found",
+		"link": "http://docs.ely.by",
+	})
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusNotFound)
+	w.Write(json)
+}