Fix to_string bug

src/lib/Enumerable.vala

@@ -179,10 +179,10 @@ namespace Invercargill {
         }
 
         public virtual string to_string(TransformDelegate<T, string> stringifier, string seperator = "") {
-            bool is_first = false;
+            bool is_first = true;
             return aggrigate<string>("", (s, v) => {
                 if(is_first) {
-                    is_first = true;
+                    is_first = false;
                     return stringifier(v);
                 }
                 return s + seperator + stringifier(v);