Improved logging

Logs are now written to System.out instead of System.err. Also they are
not duplicated as the default ConsoleHandler has been removed.

When using the application, logs may not appear in the console
immediately as the StreamHandler used to output them used an internal
buffer that may only be flushed when closing the application.

Logs are now formatted as [DATE TIME] [LEVEL] [LOGGER] MSG

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

@@ -59,7 +59,7 @@ public class Startup {
 			System.exit(1);
 			e.printStackTrace();
 		}
-		
+
 		// Set new logger levels loaded from config
 		EnvoyLog.setFileLevelBarrier(config.getFileLevelBarrier());
 		EnvoyLog.setConsoleLevelBarrier(config.getConsoleLevelBarrier());