[PATCH] doc: add README.md especially for github

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:

> On Fri, Oct 24 2014, David Bremner <david at tethera.net> wrote:
>
>> Apparently README.md overrides README, so this will show up instead of
>> our generic README on github.
>>
>> If the user is already on github, then clicking a link for more
>> information is not a hardship.
>
> LGTM. although I'd prefer README.rst
>

OK, rst version pushed and shows up on github.

d