Fix encoding for appended strings

If a packet is constructed using the expression form, PacketStringUtils will encode properly the string like this:
String latin = new String(actualString.toString().getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);

This does not happen if the packet is constructed using the Object... constructor,
and packets like this:

 new HPacket(10, 2, 100000, "Dragón de Fuego Azul", 3).toExpression();

 will show � instead of ó.
 Whereas:

 new HPacket("{l}{h:10}{i:2}{i:100000}{s:\"Dragón de Fuego Azul\"}{i:3}").toExpression();

 would display the string correctly.

G-Earth/src/main/java/gearth/protocol/HPacket.java

@@ -491,6 +491,7 @@ public class HPacket implements StringifyAble {
         return this;
     }
     public HPacket appendString(String s) {
+        s = new String(s.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
         return appendString(s, StandardCharsets.ISO_8859_1);
     }