[Asterisk-Dev] Passing overlap digits from one pri-E1 to another

[Peter Svensson]

We were having three problems:
 * No dialtone on the pri line even with immediate=no
     - solved by adding the same lines as are used for non-pri zaptel
       interfaces to give dialtone.

 * Overlap digits were not accepted once the channel was proceeding
     - solved by allowing incoming overlap digits in that state as
       well in libpri/q931.c

 * Digits dialled really fast were lost
     - The digits are lost when zt_digit() in chan_zap.c is called
       before setup_ack has been received from the network. They 
       really need to be queued in this case. I made a test-workaround
       by adding a usleep(500000) to app_dial.c in wait_for_answer(). This 
       allowed all the digits to pass. I am not sure how to fix this 
       correctly.

Peter