New command "chat_command" added to CHAN_CAPI

(from README.media)

chat_command

Description:
Used to send command to conference.

Supported hardware:
Diva

Syntax:
capicommand(chat_command|options|roomname)
options - mandatory
r - Remove newest user from conference.
Command does not apply to calling member and be used by operators only.
l - Remove all listeners from conference.
Command does not apply to calling member and be used by operators only.
o - Remove all operators from conference.
Command does not apply to calling member and be used by operators only.
a - Remove all users from conference.
Command does not apply to calling member and be used by operators only.
roomname - optional, room caller assigned to is used if not present

Syntax example:
exten => s,n,capicommand(chat_command|r)
exten => s,n,capicommand(chat_command|lo|test)
exten => s,n,capicommand(chat_command|a|test)

Conference example:
/////////////////////////////////////////////////////////////////////
[isdn-in]
exten => _X.,1,Answer
exten => _X.,n,Authenticate(12345)
exten => _X.,n,Playback(vm-rec-name)
exten => _X.,n,Record(/tmp/name${UNIQUEID}.alaw,5,15) ; Record name
exten => _X.,n,capicommand(chat_play|c1||/tmp/name${UNIQUEID}.alaw|1-4) ; Play name to conference
exten => _X.,n,capicommand(resource|1-4) ; Create resource PLCI if call from IP
exten => _X.,n,capicommand(clamping|200) ; Activate suppression of DTMF codes
exten => _X.,n,capicommand(vc|chat_mute|1|yes) ; Voice command, key 1 - mute all members except operators
exten => _X.,n,capicommand(vc|chat_mute|2|no) ; Voice command, key 2 - unmute all members except operators
exten => _X.,n,capicommand(vc|chat_command|0|a|c1) ; Voice command, key 0 - remove all members from conference
exten => _X.,n,capicommand(vc|noisesuppressor|3|yes) ; Voice command, key 3 - turn noise suppression on
exten => _X.,n,capicommand(vc|noisesuppressor|4|no) ; Voice command, key 4 - turn noise suppression off
exten => _X.,n,capicommand(chat|c1|mo|1-4) ; Add caller to conference as operator