Add a LocalDB auto save mechanism

During startup, a timer is initialized inside the LocalDB which saves it
after 500 milliseconds during startup and then in intervals of 2
minutes, which can be configured in the ClientConfig.

client/src/main/java/envoy/client/data/ClientConfig.java

@@ -35,6 +35,7 @@ public final class ClientConfig extends Config {
 		put("server", "s", identity());
 		put("port", "p", Integer::parseInt);
 		put("localDB", "db", File::new);
+		put("localDBSaveInterval", "db-si", Integer::parseInt);
 	}
 
 	/**
@@ -54,4 +55,10 @@ public final class ClientConfig extends Config {
 	 * @since Envoy Client v0.1-alpha
 	 */
 	public File getLocalDB() { return (File) items.get("localDB").get(); }
+
+	/**
+	 * @return the amount of minutes after which the local database should be saved
+	 * @since Envoy Client v0.2-beta
+	 */
+	public Integer getLocalDBSaveInterval() { return (Integer) items.get("localDBSaveInterval").get(); }
 }

client/src/main/java/envoy/client/data/LocalDB.java

@@ -160,6 +160,20 @@ public final class LocalDB implements EventListener {
 			.forEach(chats::add);
 	}
 
+	/**
+	 * Initializes a timer that automatically saves this local database after a
+	 * period of time specified in the settings.
+	 *
+	 * @since Envoy Client v0.2-beta
+	 */
+	public void initAutoSave() {
+		new Timer("LocalDB Autosave", true).schedule(new TimerTask() {
+
+			@Override
+			public void run() { save(); }
+		}, 2000, ClientConfig.getInstance().getLocalDBSaveInterval() * 60000);
+	}
+
 	/**
 	 * Stores all users. If the client user is specified, their chats will be stored
 	 * as well. The message id generator will also be saved if present.

client/src/main/java/envoy/client/ui/Startup.java

@@ -226,5 +226,8 @@ public final class Startup extends Application {
 				else trayIcon.hide();
 			});
 		}
+
+		// Start auto save thread
+		localDB.initAutoSave();
 	}
 }

client/src/main/resources/client.properties

@@ -1,8 +1,6 @@
 server=localhost
 port=8080
 localDB=localDB
-password=
-user=
-ignoreLocalDB=false
+localDBSaveInterval=2
 consoleLevelBarrier=FINER
 fileLevelBarrier=OFF