bug 296 - part 1 FAILOVER fixes

This change allows a non-origin node to be specified on the FAILOVER command
so that subscriptions for these nodes are not redirected to the backup node.

An array of all the failed nodes (in addition to the one being failed over at this
stage of the process) is now passed to many of the failover stored functions

This commit also adds the SiteFailover unit test that tests multiple nodes in a site
failing over when the cluster does not have a complete path network
DROP NODE will now pass all nodes being dropped to the stored functions and event

This allows slony to detect if a provider that is being dropped
only provides the subscription to some other node that is also
being dropped.

Also update the unit tests to reflect the new method
of FAILOVER involving provider-only nodes
removing unused variables introduced in the previous commits
documentation updates (FAILOVER)
fixing unit test, issue a sync to make sure the nodes have
caught up before doing the compareDb
Save the return code for the next iteration

If the moveSet fails as part of a failover we continue processing
for the other nodes.  This fix make sure that we remember any failures
and slonik will return a non-zero return code when finished
ensure that the transactions are closed as part of the FAILOVER before doing a MOVE SET

There were some code paths that could leave a transaction open such that when we later
got to a second set or node the LOCK SET could fail.

Also remove an unused if condition
Documentation fixes for EXECUTE SCRIPT
improve the error case detection of slony_logshipper

This commit will give a better error message when the log shipper connects to
a databse without the sl_archive_tracking tables.
bug 298 - process DDL_SCRIPT events from the log shipper SQL files
Add a test to LogShipping.js that tests DDL on logshipping nodes
bug 297 - fix test_slony_state-dbi.pl so that it works with PG 9.2

Also fix the warning emails for sl_confirm and sl_event checks so that they
actually treat problem conditions as problems.
documentation updates for log shipping

Make the slony_logshipper daemon have a proper page in the reference section
like slon and slonik.  Clean up the rest of the logshipping instructions to be
more of a set of instructions versus question/answer format.
Initial version of a perl script to convert the new
COPY protocol style log shipping files to pure
SQL ones (INSERT,UPDATE,DELETE,TRUNCATE..)
add DDL_SCRIPT translation to the logshipping_toinsert
more documentation items
removing stray quote
Small fixes for failover code.
Merge branch 'bug297'
Merge branch 'bug298'