bug 304 - record sequence values as part of a EXECUTE_SCRIPT

Prior to 2.2 the EXECUTE_SCRIPT command result in a DDL_SCRIPT event
and a SYNC event generated as part of the same transaction. That
SYNC event also replicates the value of any sequences to the replica
before the DDL SCRIPT command.

In 2.2 the DDL script is replicated as part of a normal SYNC
as rows in sl_log_script.  This commit stores any sequence changes
as extra elements in the cmdargs array.  These sequence values are
then set before the DDL_SCRIPT is executed on the replica

This commit includes a unit test change to reproduce this issue
the test now passes
Allow the apply trigger to work (ie not fail) on sl_log_script rows from earlier betas of 2.2.0
Revisions to DDL docs
Add release note on #304
Merge branch 'bug304' of github.com:ssinger/slony1-engine into bug304
Fix typo in sample data
create string_agg in slony1_base.sql not slony1_funcs.sql

If the CREATE AGGREGATE is in slony1_funcs.sql it will fail on an update functions
since the aggregate already exists.  As part of the upgrade we will check
to see if we need to create the aggregate.
deconstruct_array wants the OID of the element type, not the array type
bug 310 - only issue the notify Restart if we actually change configuration

The FAILOVER_NODE event is processed in two parts by slon.
First failedNode(..) is called which reconfigures sl_subscribe,
sl_path and then the listen network. Once this is done notify
is used to signal the slon to restart.

Then the slon commits this transactions and waits for any
pending events from the failed origin to arrive from a third
provider. Slon then continues with the failover (failoverSet_int).

The problem was that when slon restarts it repeats the processing
the FAILOVER_NODE. It was possible for slon to keep restarting
before it gets to be caught up and recording the FAILOVER_NODE
event as processed.

In this patch we only restart slon if the configuration actually
is changed. After the first restart the configuration shouldn't
need changing so there should not be anymore restarts.
Merge branch 'bug304'
bug 309 - make sure sl_failover_targets gets created when upgrading to 2.2
Bug 311 - Don't include performance.sgml ( 'man') file twice in the tar
Merge branch 'bug310'
release notes update
Updating version numbers to 2.2.0 rc1
variable declarations must be at the start of the block (VC does still enforces this)
release notes update
BUG308 : added TCP KEEP ALIVE configurations in slon.conf-sample
Merge branch 'master' of ssh://git.postgresql.org/slony1-engine

Conflicts:
	RELEASE
	doc/adminguide/ddlchanges.sgml
Reorganize release notes for 2.2