Update host list format to be

<ip_address>,<name>
to make end user display and interpretation easier

src/target_state.rs

@@ -1,8 +1,9 @@
 use std::net::Ipv4Addr;
 use std::time::SystemTime;
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct TargetState {
+    pub name: String,
     pub target: Ipv4Addr,
     pub alive: bool,
     pub last_rtt: u32,
@@ -12,6 +13,7 @@ pub struct TargetState {
 impl Default for TargetState {
     fn default() -> Self {
         TargetState {
+            name: "Unknown Host".to_string(),
             target: Ipv4Addr::new(127, 0, 0, 1),
             alive: false,
             last_rtt: 0,