Only create Stasis subscriptions when enabled

Subscribing to Stasis isn't free.

As such, this patch makes AMI, CDR, and CEL - the "big 3" - only subscribe
when enabled. Toggling their availability via a .conf file will
unsubscribe/subscribe as appropriate.

Review: https://reviewboard.asterisk.org/r/2888/
........

Merged revisions 400312 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@400313 f38db490-d61c-443f-a65b-d21fe96a405b
Cast Integer Argument To Unsigned Char

The member reg in the peercnt structure is an unsigned char and peercnt_modify()
is expecting an unsigned char argument which gets assigned to peercnt->reg.

This patch fixes that by casting the integer argument being passed to
peercnt_modify to unsigned char.
........

Merged revisions 400314 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 400315 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 400316 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@400317 f38db490-d61c-443f-a65b-d21fe96a405b