DTMF CallerID detection problems.

DTMF CallerID detection problems.

The code handling DTMF CallerID drops digits on long CallerID numbers and
may timeout waiting for the first ring with shorter numbers.

The DTMF emulation mode was not turned off when processing DTMF CallerID.
When the emulation code gets behind in processing the DTMF digits it can
skip a digit.

For shorter numbers, the timeout may have been too short.  I increased it
from 2 seconds to 4 seconds.  Four seconds is a typical time between rings
for many countries.

(closes issue #16460)
Reported by: sum
Patches:
      issue16460.patch uploaded by rmudgett (license 664)
      issue16460_v1.6.2.patch uploaded by rmudgett (license 664)
Tested by: sum, rmudgett

Review: https://reviewboard.asterisk.org/r/634/

JIRA SWP-562
JIRA AST-334
JIRA SWP-901

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@260195 65c4cc65-6c06-0410-ace0-fbb531ad65f3