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

store/src/leaf_set.rs

@@ -25,7 +25,6 @@ use core::core::hash::Hashed;
 use core::core::pmmr;
 use core::core::BlockHeader;
 use prune_list::PruneList;
-use util::LOGGER;
 
 /// Compact (roaring) bitmap representing the set of positions of
 /// leaves that are currently unpruned in the MMR.
@@ -64,7 +63,7 @@ impl LeafSet {
 		let cp_file_path = Path::new(&cp_path);
 
 		if !cp_file_path.exists() {
-			debug!(LOGGER, "leaf_set: rewound leaf file not found: {}", cp_path);
+			debug!("leaf_set: rewound leaf file not found: {}", cp_path);
 			return Ok(());
 		}
 
@@ -73,10 +72,7 @@ impl LeafSet {
 		bitmap_file.read_to_end(&mut buffer)?;
 		let bitmap = Bitmap::deserialize(&buffer);
 
-		debug!(
-			LOGGER,
-			"leaf_set: copying rewound file {} to {}", cp_path, path
-		);
+		debug!("leaf_set: copying rewound file {} to {}", cp_path, path);
 
 		let mut leaf_set = LeafSet {
 			path: path.clone(),