addons/chan_mobile: Increase buffer size of UCS2 encoded SMS messages

When UCS2 character encoding is used, one symbol in national language can be
expanded to 4 bytes. The current buffer used for receiving message in
do_monitor_phone is 256 bytes, which is not large enough for incoming messages.

For example:
* AT+CMGR phone response prefix
  '+CMGR: "REC UNREAD","+7**********",,"14/10/29,13:31:39+12"\r\n' - 60 bytes
* SMS body with UCS2 encoding (max) - 280 bytes
* AT+CMGR phone response suffix '\r\n\r\nOK\r\n' - 8 bytes
* Terminating null character - 1 byte

This results in a needed buffer size of 349 bytes. Hence, this patch opts for a
350 byte buffer.

ASTERISK-24468 #close
Reported by: Dmitriy Bubnov
patches:
  chan_mobile-1_8.diff uploaded by Dmitriy Bubnov (License 6651)
  chan_mobile-trunk.diff uploaded by Dmitry Bubnov (License 6651)
........

Merged revisions 427607 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@427610 f38db490-d61c-443f-a65b-d21fe96a405b
channels/chan_mgcp: Fix regression which causes gateways to be skipped

In r227276, a while loop was turned into a for loop. Unfortunately, a portion
of the while loop was left in the code such that, when a static gateway is
encountered in the list of MGCP gateways, the next gateway would be skipped.
At best, we would simply flip past a gateway; at worst, this could lead to a
crash.

ASTERISK-24500 #close
Reported by: Xavier Hienne
patches:
  chan_mgcp.patch uploaded by Xavier Hienne (License 6657)
........

Merged revisions 427613 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@427614 f38db490-d61c-443f-a65b-d21fe96a405b
Blocked revisions 427617

........
configs/features.conf: Add documentation noting potential chan_agent conflict

In chan_agent, a '*' is used by default to terminate a bridge with a caller.
This can lead to all sorts of problems if '*' is used by a feature in
features.conf, as the chan_agent disconnect '*' may be detected first.

This patch adds a documentation snippet to features.conf so that users who
attempt to use features with agents know of the potential conflict.

ASTERISK-20402 #close
Reported by: Matt Riddell
patches:
  features.conf.diff uploaded by Matt Riddell (License 5023)


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@427618 f38db490-d61c-443f-a65b-d21fe96a405b