Update to A/T-based telephony features

[Lebbeous Fogle-Weekley]

For Evergreen master / 2.2:

    New features for telephony currently in use at KCLS

    I must ask the community's forgiveness for sitting on this for so long.
    This code was developed in fits over time, and it had to be disentangled
    from some site-specific configuration and workarounds before it could
    be usefully published.

    Enhancements over what's already committed to master include:

    - a feature that allows an Evergreen system to query the PBX (where
      PBX here refers to an Asterisk system plus the eg-pbx-* scripts from
      Evergreen - particularly eg-pbx-mediator.pl) for the A/T event IDs
      associated with failed notifcations, so that those A/T events can be
      "rolled over" into new ones with a different event definition, and
      thus a different notification method.

    - holiday awareness in eg-pbx-allocator (the piece run by cron whose
      main responsibility is dripping files from a staging directory into
      Asterisk's real spool for call files). There's a script (set_pbx_holidays
      that can be run by cron on an Evergreen system to periodically update the
      PBX's table of holidays based on a given org unit's closed_date ranges.

    - smart retry. In certain situations, if you put too many callfiles
      into Asterisk's spool at once, Asterisk will try to make too many
      calls at once, and all such calls just fail. That's what the
      allocator is meant to prevent. Smart retry is about moving calls that
      have been tried once, and will be retried again later due to resulting
      in a busy signal or other problem, out of the spool to make room for
      other calls that could be made in the mean time.

    - miscellaneous helper scripts and things for spreading more
      reportable/greppable information among A/T output and cleaning up
      callfiles that result in no-op's for Asterisk. Lock file checking for
      the allocator. Etc.

    I also have tried to throw in some useful documentation. I admit things
    look a bit jumbled, but I'll be as available as I can make myself to help
    anyone who steps up to clarify documentation or improve code in order to
    make general adoption of these features a little easier.

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/senator/telephony-update

[Mike Rylander (mrylander)]

Merged to master. Telephony! Yeah!