asterisk-1.8.x: update to 1.8.31.0

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>
asterisk-11.x: update to 11.13.0

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>
asterisk-chan-sccp-b: update to rev 5151

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>
Merge branch 'master' of http://git.openwrt.org/feed/telephony