remove the sites-enabled readme

this file is considered a site config  file, preventing the use of the repo as is
Ensure compatibility with earlier/current versions of nginx

auto was not introdued until 1.3.8 and 1.2.5.

Debian wheezy for example only comes with 1.2.1, only the next version
(in testing) will have a version of nginx which supports auto.
rename conf folder to h5bp

The name "conf" is potentially confusing as something which should be inclued
en masse rather than a folder of config snippets.

Closes #13
Add a config file for no default site

fixes #10