app_confbridge: Can now set the language used for announcements to the conference.

ConfBridge now has the ability to set the language of announcements to the
conference.  The language can be set on a bridge profile in
confbridge.conf or by the dialplan function
CONFBRIDGE(bridge,language)=en.

(closes issue ASTERISK-19983)
Reported by: Jonathan White
Patches:
      M19983_rev2.diff (license #5138) patch uploaded by junky (modified)
Tested by: rmudgett
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Merged revisions 400741 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 400742 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@400744 f38db490-d61c-443f-a65b-d21fe96a405b
Switch from using pjsip_strerror to pj_strerror.

pjsip_strerror is only aware of PJSIP-specific error
codes. pj_strerror() is aware of all PJProject error
codes and OS-specific error codes.

This specifically fixes an oft-seen error in transport
configuration code where EADDRINUSE would result in
"Unknown PJSIP error 120098" instead of a useful
message.
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Merged revisions 400749 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@400750 f38db490-d61c-443f-a65b-d21fe96a405b