Refactor Werkzeug requirement into flask

This is a PR is a rewrite of the code base that replaces the server code with a Flask implementation - see issue #38  and PR #40  for full discussions.  Thanks to @jeromekelleher and @kerrydc for the help and feedback.
I was gonna put "Hello world" but thought this may be more relevant.  I
want something here so I can know that the server is alive by launching my
browser.

On Wed Dec 10 2014 at 2:02:41 PM Kerry Donny-Clark <notifications@github.com>
wrote:

> In ga4gh/server/views.py
> <https://github.com/ga4gh/server/pull/45#discussion-diff-21627179>:
>
> > +    """
> > +    Handles the specified HTTP OPTIONS request returing a werkzeug
> > +    response.
> > +    """
> > +    response = wzw.Response("", mimetype="application/json")
> > +    # TODO is this correct CORS support?
> > +    response.headers.add("Access-Control-Allow-Origin", "*")
> > +    response.headers.add(
> > +        "Access-Control-Request-Methods", "GET,POST,OPTIONS")
> > +    response.headers.add("Access-Control-Allow-Headers", "Content-Type")
> > +    return response
> > +
> > +
> > +@app.route('/')
> > +def index():
> > +    return "ATGC"
>
> Why this string?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/ga4gh/server/pull/45/files#r21627179>.
>