Improves console and GUI messages

Adds newlines when writing to console
Add Error: on lines containing an error
Makes it clearer when a jar build is successful
Makes failures show errors rather than throwing exceptions

src/test/java/net/knarcraft/minecraftserverlauncher/userinterface/FakeGUI.java

@@ -21,6 +21,7 @@ public class FakeGUI extends MessageHandler implements GUI {
     public void setStatus(String message) {
         try {
             writer.write(message);
+            writer.newLine();
             writer.flush();
         } catch (IOException e) {
             System.out.println(message);