Add timestamp to log messages

To help with debugging Alacritty issues, a timestamp and the error
level have been added to all log messages.

All log messages now follow this format:
    [YYYY-MM-DD HH:MM] [LEVEL] Message

Cargo.lock

@@ -56,6 +56,7 @@ dependencies = [
  "static_assertions 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "terminfo 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "vte 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",

Cargo.toml

@@ -49,6 +49,7 @@ image = "0.20.1"
 static_assertions = "0.2.5"
 terminfo = "0.6.1"
 url = "1.7.1"
+time = "0.1.40"
 
 [target.'cfg(any(target_os = "linux", target_os = "freebsd", target_os="dragonfly", target_os="openbsd"))'.dependencies]
 x11-dl = "2"

src/lib.rs

@@ -64,6 +64,7 @@ extern crate xdg;
 extern crate base64;
 extern crate terminfo;
 extern crate url;
+extern crate time;
 
 #[macro_use]
 pub mod macros;

src/logging.rs

@@ -19,6 +19,7 @@
 //! log-level is sufficient for the level configured in `cli::Options`.
 use cli;
 use log::{self, Level};
+use time;
 
 use std::env;
 use std::fs::{File, OpenOptions};
@@ -121,12 +122,19 @@ impl log::Log for Logger {
 
     fn log(&self, record: &log::Record) {
         if self.enabled(record.metadata()) && record.target().starts_with("alacritty") {
+            let msg = format!(
+                "[{}] [{}] {}\n",
+                time::now().strftime("%F %R").unwrap(),
+                record.level(),
+                record.args()
+            );
+
             if let Ok(ref mut logfile) = self.logfile.lock() {
-                let _ = logfile.write_all(format!("{}\n", record.args()).as_ref());
+                let _ = logfile.write_all(msg.as_ref());
             }
 
             if let Ok(ref mut stdout) = self.stdout.lock() {
-                let _ = stdout.write_all(format!("{}\n", record.args()).as_ref());
+                let _ = stdout.write_all(msg.as_ref());
             }
 
             match record.level() {