pgsql: vcbuild updates from Magnus: * After Markos patch, now builds

Log Message:
-----------
vcbuild updates from Magnus:

* After Markos patch, now builds pgcrypto without zlib again
* Updates README with xml info
* xml requires xslt and iconv
* disable unnecessary warning about __cdecl()
* Add a buildenv.bat called from all other bat files to set up things
like PATH for flex/bison. (Can't just set it before calling, doesn't
always work when building from the GUI)

Modified Files:
--------------
    pgsql/src/tools/msvc:
        Project.pm (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/Project.pm.diff?r1=1.5&r2=1.6)
        README (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/README.diff?r1=1.1&r2=1.2)
        Solution.pm (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/Solution.pm.diff?r1=1.5&r2=1.6)
        build.bat (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/build.bat.diff?r1=1.3&r2=1.4)
        mkvcbuild.pl (r1.9 -> r1.10)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/mkvcbuild.pl.diff?r1=1.9&r2=1.10)
        pgbison.bat (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/pgbison.bat.diff?r1=1.2&r2=1.3)
        pgflex.bat (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/msvc/pgflex.bat.diff?r1=1.2&r2=1.3)