Feature: minimize to SysTray option on the settings screen (#246)

* Feature: minimize to SysTray on the settings screen

src/com/sheepit/client/Configuration.java

@@ -62,6 +62,7 @@ import lombok.Data;
 	private List<Pair<Calendar, Calendar>> requestTime;
 	private String extras;
 	private boolean autoSignIn;
+	private boolean useSysTray;
 	private String UIType;
 	private String hostname;
 	private String theme;
@@ -90,6 +91,7 @@ import lombok.Data;
 		this.requestTime = null;
 		this.extras = "";
 		this.autoSignIn = false;
+		this.useSysTray = true;
 		this.UIType = null;
 		this.theme = null;
 	}