Improved PUA DialogInfo.

Several fixes here:
  - Dialog callbacks are now correctly setup after a restart of
    OpenSIPS. In other words, restarting OpenSIPS will not lead to ghost BLFs
    anymore.
  - Added an option allowing not to publish state change in case of reINVITE.
  - Added an option allowing not to publish state change in trying state.
    In other words, a PUBLISH will be sent only when OpenSIPS has received a
    18x response type and not before.