pgsql: Improve "pg_ctl -w start" server detection by writing the postma

Improve "pg_ctl -w start" server detection by writing the postmaster
port and socket directory into postmaster.pid, and have pg_ctl read from
that file, for use by PQping().

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=075354ad1bc0496c30dbd4dafb0f88a4d3e54cbc

Modified Files
--------------
doc/src/sgml/ref/pg_ctl-ref.sgml  |   51 +---------
src/backend/utils/init/miscinit.c |   30 ++++---
src/bin/pg_ctl/pg_ctl.c           |  189 ++++++++++++++++++-------------------
3 files changed, 112 insertions(+), 158 deletions(-)