Log Message:
Import skytools-3.1.5 as databases/skytools.
Based on PR pkg/48639 by rudolf.

SkyTools is a package of tools in use in Skype for replication and failover.
It also includes a generic queuing mechanism called PgQ and a utility
library for Python scripts, as well as a script for setting up and managing
WAL based standby servers.

PgQ is a queuing system written in PL/pgSQL, Python and C code. It is based
on snapshot-based event handling ideas from Slony-I, and is written for
general usage. PgQ provides an efficient, transactional, queueing system
with multi-node support (including work sharing and splitting, failover and
switchover, for queues and for consumers). PgQ is split into 3 layers:
Producers, Ticker and Consumers.

Londiste is a replication tool written in Python, using PgQ as event
transport.

Walmgr is a script that will setup WAL archiving, does the initial backup,
and runtime WAL archive and restore. It can also be used for
up-to-last-second partial file copying, so that less than the whole file is
lost in case of loss of the master database server.