Update from 1.3.5 to 1.3.6.

<ChangeLog>

*) Feature: the ngx_http_gunzip_filter_module.

*) Feature: the "memcached_gzip_flag" directive.

*) Feature: the "always" parameter of the "gzip_static" directive.

*) Bugfix: in the "limit_req" directive; the bug had appeared in 1.1.14.

Thanks to Charles Chen.

*) Bugfix: nginx could not be built by gcc 4.7 with -O2 optimization if

the --with-ipv6 option was used.

</ChangeLog>