KAZOO-2077: check context of events/dialplan requests

check context of events/dialplan requests and only handle those coming from the
configured Kazoo context.
KAZOO-2077: manually set call stat to abandoned
KAZOO-2077: pass along the hangup to the FSM
KAZOO-2077: log the status of the channel
KAZOO-2077: logging and formatting
KAZOO-2077: handle missing views
KAZOO-2077: add newlines to output
KAZOO-2077: handle if there's a cdr url to post to
KAZOO-2077: don't check channel aliveness on re_req
KAZOO-2077: bind for destroy
KAZOO-2077: remove cb_context record access