Replace logging backend to log4rs and add log rotation (#1789)

* Replace logging backend to flexi-logger and add log rotation
* Changed flexi_logger to log4rs
* Disable logging level filtering in Root logger
* Support different logging levels for file and stdout
* Don't log messages from modules other than Grin-related
* Fix formatting
* Place backed up compressed log copies into log file directory
* Increase default log file size to 16 MiB
* Add comment to config file on log_max_size option

servers/src/webwallet/server.rs

@@ -25,8 +25,6 @@ use std::env;
 use std::io::Error;
 use std::thread;
 
-use util::LOGGER;
-
 /// Future returned from `MainService`.
 enum MainFuture {
 	Root,
@@ -94,10 +92,7 @@ pub fn start_webwallet_server() {
 			let server = Server::bind(&addr)
 				.serve(|| future::ok::<_, Error>(MainService::new()))
 				.map_err(|e| eprintln!("server error: {}", e));
-			warn!(
-				LOGGER,
-				"Grin Web-Wallet Application is running at http://{}/", addr
-			);
+			warn!("Grin Web-Wallet Application is running at http://{}/", addr);
 			rt::run(server);
 		});
 }