pgsql: Include the platform "FAQs" into the installation instructions.

Log Message:
-----------
Include the platform "FAQs" into the installation instructions.
I weeded out some really old information along the way.
FAQ_AIX needs separate consideration and will be dealt with later.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        install-win32.sgml (r1.49 -> r1.50)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/install-win32.sgml?r1=1.49&r2=1.50)
        installation.sgml (r1.313 -> r1.314)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/installation.sgml?r1=1.313&r2=1.314)

Removed Files:
-------------
    pgsql/doc:
        FAQ_CYGWIN
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_CYGWIN)
        FAQ_HPUX
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_HPUX)
        FAQ_IRIX
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_IRIX)
        FAQ_MINGW
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_MINGW)
        FAQ_SCO
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_SCO)
        FAQ_Solaris
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/FAQ_Solaris)