add LG 27GL850-B (GSM5B7F) closes #218

[momumi]

The "27GL850-B" is also sometimes called just "27GL850". They are the same.

Managed to get most of the settings working, though the colortemmanual and gammamode need to write 16 bit registers to work which ddccontrol gui doesn't seem to handle properly (see ddccontrol/ddccontrol#85). However, you can set 16 bit registers on the CLI with ddcutil like:

# set gamma mode
ddcutil -b 8 setvcp 0x72 0x6400

# set color temperature (needs `-f` (force) to work)
ddcutil -f -b 8 setvcp 0x69 7500

Also note that most settings cannot be controlled unless you use either the Gamer 1 or Gamer 2 profile. These are custom profiles and will remember your settings when you switch back to them. The other profiles are just presets which only allow you to change some basic settings (eg brightness).

[mirh]

(prot(monitor)type(lcd)GN850cmds(01 02 03 0C E3 F3)vcp(02 04 05 08 10 12 14(05 08 0B ) 16 18 1A 52 60( 11 12 0F 10) AC AE B2 B6 C0 C6 C8 C9 D6(01 04) DF 62 8D F4 F5(00 01 02) F6(00 01 02) 4D 4E 4F 15(01 06 09 10 11 13 14 28 29 32  44 48) F7(00 01 02 03) F8(00 01) F9 EF FD(00 01) FE(00 01 02) FF)mccs_ver(2.1)mswhql(1))

This is what I got on a 27GN850 instead. It's interesting, because this is like the first time I could know/notice/distinguish purely from the software that this is isn't actually a 27GL850.