TCP tests via telnet.

Hi!

@sompylasar, @deathbaba, another small test for me. If looks good, safe to merge; this pull request goes to my local master, and will thus augment the currently pending one with HTTP tests.

I plan to keep ```curl``` / ```telnet``` tests in the code as ```DISABLED_``` tests, replacing them by native clients side-by-side.

Thanks,
Dima