a '+' separated list of DTMF strings

Each element in the list can contain an @ followed by
a duration in ms.

e.g.
1234@250+4321@500

sends the digits 1 2 3 4 at a rate of 250ms then
4 3 2 1 at a rate of 500




git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@7193 d0543943-73ff-0310-b7d9-9358b9ac24b2