log: route task/component status output through logging, not print()

AttributeChange (the common base of every ATask and component ABC) now
sets self.log = logging.getLogger(type(self).__name__), so components
no longer need to hand-type their own name into each message. Wired
logging.basicConfig() in server/brewpi.py with a bare "%(name)s:
%(message)s" formatter - Tee (see prior commit) still supplies the
"<date>T<time>:" prefix, so lines read "<date>T<time>:<component>:
<message>" without double-stamping, and third-party loggers
(websockets, asyncio) now get the same formatting for free.

Converted the print() call sites that were standing in for this in
tasks/ and components/ (leaving __main__ demo blocks and explicit
debug-dump helpers alone).

server/brewpi.py

@@ -2,6 +2,7 @@
 import asyncio
 import functools
 import json
+import logging
 import os
 import signal
 import sys
@@ -20,20 +21,23 @@ from tasks import TaskManager, TempSensorTask, HeaterTask, PotTask, TcTask, Stir
 
 import argparse as ap
 
+log = logging.getLogger('brewpi')
+
 
 class Tee:
 	"""Duplicates writes to multiple streams - used to mirror stdout/stderr
-	(everything the rest of the codebase already reaches via print()) into
-	a log file under logs/ as well as the console, without having to touch
-	every print() call site.
+	into a log file under logs/ as well as the console, without every
+	writer needing to know about either.
 
-	Also stamps every line with a "<date>T<time>:" prefix (existing print()
-	call sites already start their message with "Component: ..." - see e.g.
-	tasks/stirrer.py - so the combined line reads
-	"<date>T<time>:<component>: <message>"), so log entries can be
-	correlated with the JSON sample logs (ServerLogTask/SudLogTask) without
-	relying on journalctl's own timestamps, which aren't present in the
-	mirrored log files themselves."""
+	Also stamps every line with a "<date>T<time>:" prefix. Every task/
+	component logs via logging (see utils/value.py's AttributeChange, which
+	gives self.log to all of them), configured below with a bare
+	"%(name)s:%(message)s" formatter - Tee supplies the timestamp instead,
+	so the combined line reads "<date>T<time>:<component>:<message>" (see
+	logging.basicConfig() call below) without double-stamping. This lets
+	log entries be correlated with the JSON sample logs (ServerLogTask/
+	SudLogTask) without relying on journalctl's own timestamps, which
+	aren't present in the mirrored log files themselves."""
 
 	def __init__(self, *streams):
 		self.streams = streams
@@ -92,7 +96,11 @@ if __name__ == '__main__':
 	latest_log_file = open(latest_log_path, "w", buffering=1)
 	sys.stdout = Tee(sys.stdout, log_file, latest_log_file)
 	sys.stderr = Tee(sys.stderr, log_file, latest_log_file)
-	print("Logging to {}".format(log_path))
+	# No "%(asctime)s" here - Tee (above) already stamps every mirrored
+	# line with "<date>T<time>:", so this only contributes the
+	# "<component>:<message>" part (see Tee's own docstring).
+	logging.basicConfig(stream=sys.stdout, level=logging.INFO, format='%(name)s:%(message)s')
+	log.info("Logging to {}".format(log_path))
 
 	config = json.load(open(args.config))
 	dispatcher = MessageDispatcher()
@@ -246,7 +254,7 @@ if __name__ == '__main__':
 	http_handler = functools.partial(SimpleHTTPRequestHandler, directory=web_dir)
 	http_server = ThreadingHTTPServer(("0.0.0.0", args.http_port), http_handler)
 	threading.Thread(target=http_server.serve_forever, daemon=True).start()
-	print("Serving {} on http://0.0.0.0:{}".format(web_dir, args.http_port))
+	log.info("Serving {} on http://0.0.0.0:{}".format(web_dir, args.http_port))
 
 	# systemd's `stop`/`restart` send SIGTERM, whose default disposition is to
 	# kill the process immediately - skipping the finally: block below
@@ -259,7 +267,7 @@ if __name__ == '__main__':
 	try:
 		loop.run_forever()
 	except KeyboardInterrupt:
-		print("\nShutting down...")
+		log.info("Shutting down...")
 	finally:
 		# Cancel all tasks so their finally blocks (e.g. HeaterTask's/
 		# StirrerTask's `with device.open()`) get a chance to run before we
@@ -278,4 +286,4 @@ if __name__ == '__main__':
 		stirrer.activate(False)
 		http_server.shutdown()
 		loop.close()
-		print("Server stopped.")
+		log.info("Server stopped.")