Feature/configuration volumes

This combines what was discussed in PR #11 but adds two levels of configuration:

- Automatic Config
     - Just run it ... `sudo docker run -d nginx:1.x`
     - You get standard config as it runs today
- New Service Config
     - Added in a volume share `/nginx/conf.d` which allows new server sections to be added on a shared volume
     - The existing server config (aka, port 80) is still in play as are all the default settings in the "http" section
- Complete Control
     - Added another share under `/nginx/conf` which gives the host complete control
     - This allows setting anything wanted in "http" section, allows dynamic template generation of core config
     - Can be done in conjunction or independently of above share

> Note: By choosing `/nginx` as a base for configuration I have opted for a non-unix directory but in effect all I'm aiming to do is provide a compact and explanatory CLI for the host. Not sure if you'll agree with my thinking but I hope so ... I tend to fall in love with my own ideas.

> Last comment ... I'm sorry I couldn't have just let PR #11 run it's course but I needed something up and running immediately that met my needs. I'd love it if this could be brought back into the fold but if not then thank you for an excellent starting point.
It would seem I was tired and thought you actually put bootstrapper in
```ENTRYPOINT```.

In that case its just the question of ```CMD``` vs ```ENTRYPOINT```, which
I won't get much into. Only one thing. When it comes to run once scripts,
would they not run every time with ```CMD```? I currently use
```ENTRYPOINT``` for setup at runtime.
Den 19 sep 2014 00:13 skrev "Ken Snyder" <notifications@github.com>:

> In 1.7/Dockerfile:
>
> >  EXPOSE 80
> > -CMD ["nginx"]
> > +ENTRYPOINT ["nginx"]
>
> I may be missing something here. Can you give me an example of where this
> would interfere?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/docker-library/nginx/pull/13/files#r17758637>.
>