improve serial hotplug (#389)

* - disable device when error indecates that the problem is not solvable on reconnect
- introduce a preOpenDelay of 2 seconds (currently value is hardcoded)

* rs232:
- make preOpenDelay available via webui
- fix preOpenDelay
- add basic usb serial detection

* - revert 3819ae7
- fix schema files

* make json checks compat with utf8+bom

* make shutdown effect a bit more flexible

effects/shutdown.py

@@ -13,21 +13,25 @@ sleepTime      = float(hyperion.args.get('speed', 1.0))*0.5
 alarmColor     = hyperion.args.get('alarm-color', (255,0,0))
 postColor      = hyperion.args.get('post-color', (255,174,11))
 off            = bool(hyperion.args.get('shutdown-enabled', False))
+initialBlink   = bool(hyperion.args.get('initial-blink', True))
+setPostColor   = bool(hyperion.args.get('set-post-color', True))
+
 width          = 12
 height         = 10
 
 imageData      = bytearray(height * width * (0,0,0))
 
 # Start the write data loop
-for i in range(6):
-	if hyperion.abort():
-		off = False
-		break
-	if i % 2:
-		hyperion.setColor(alarmColor[0], alarmColor[1], alarmColor[2])
-	else:
-		hyperion.setColor(0, 0, 0)
-	time.sleep(sleepTime)
+if initialBlink:
+	for i in range(6):
+		if hyperion.abort():
+			off = False
+			break
+		if i % 2:
+			hyperion.setColor(alarmColor[0], alarmColor[1], alarmColor[2])
+		else:
+			hyperion.setColor(0, 0, 0)
+		time.sleep(sleepTime)
 
 for y in range(height,0,-1):
 	if hyperion.abort():
@@ -39,11 +43,12 @@ for y in range(height,0,-1):
 	time.sleep(sleepTime)
 time.sleep(1)
 
-for y in range(height):
-	for x in range(width):
-		setPixel(x, y, postColor)
-hyperion.setImage(width, height, imageData)
-time.sleep(2)
+if setPostColor:
+	for y in range(height):
+		for x in range(width):
+			setPixel(x, y, postColor)
+	hyperion.setImage(width, height, imageData)
+	time.sleep(2)
 
 if off and not hyperion.abort():
 	subprocess.call("halt")