add get_brightness() & set_brightness() functions to CFontz{633,Packet}.c

and normalize the brightness to range [0, 1000] to support changing the
brightness online

LCDd.conf

@@ -161,13 +161,13 @@ Reboot=no
 
 # Select the output device to use [default: /dev/lcd]
 Device=/dev/ttyS0
-# Select the LCD type (size) [default: 20x4]
+# Select the LCD type (size) [default: 16x2]
 Size=16x2
 # Set the initial contrast [default: 140; legal: 0 - 1000]
 Contrast=140
-# Set the initial brightness [default: 100; legal: 0 - 255]
-Brightness=100
-# Set the initial off-brightness [default: 0; legal: 0 - 255]
+# Set the initial brightness [default: 1000; legal: 0 - 1000]
+Brightness=1000
+# Set the initial off-brightness [default: 0; legal: 0 - 1000]
 # This value is used when the display is normally
 # switched off in case LCDd is inactive
 OffBrightness=50
@@ -271,6 +271,9 @@ ConnectionType=4bit
 # You may also need to configure the keypad layout further on in this file.
 Keypad=no
 
+# set the initial contrast (for bwctusb only) [default: 0; legal: 0 - 1000]
+Contrast=0
+
 # If you have a switchable backlight.
 Backlight=no