Clarify documentation about "peer" rows in window functions

Peer rows are matching rows when ORDER BY is specified.

Report by arnaud.mouronval@gmail.com, David G Johnston
pg_upgrade:  preserve the timestamp epoch

This is useful for replication tools like Slony and Skytools.

Report by Sergey Konoplev
Report timezone offset in pg_dump/pg_dumpall

Use consistent format for all such displays.

Report by Gavin Flower
Properly document that -r is only honored from the command-line.

This is for postgres/postmaster options.

Report by Tom Lane

Backpatch through 9.4
docs:  Improve pg_isready details about username/dbname

Report by Erik Rijkers

Backpatch through 9.4
Tab completion for ALTER .. ALL IN TABLESPACE

Update the tab completion for the changes made in
3c4cf080879b386d4ed1814667aca025caafe608, which rework 'MOVE ALL' to be
'ALTER .. ALL IN TABLESPACE'.

Fujii Masao

Back-patch to 9.4, as the original change was.
Documentation fix: sum(float4) returns float4, not float8.

The old claim is from my commit d06ebdb8d3425185d7e641d15e45908658a0177d of
2000-07-17, but it seems to have been a plain old thinko; sum(float4) has
been distinct from sum(float8) since Berkeley days.  Noted by KaiGai Kohei.

While at it, mention the existence of sum(money), which is also of
embarrassingly ancient vintage.