Add tests for options and socket connectivity

[p0pr0ck5]

This requires mocking out a simple sockproc server, provided as an included Perl module. This also requires upstream merging https://github.com/openresty/test-nginx/pull/46 so that tcp_reply evals can eval a Perl sub.

I know you also mentioned reworking some options handling, so some of these may need adjustment or become invalid, but I figure it's worth getting the ball rolling.