git: add a .gitignore file
fabfile: annotate tasks with @task
fabfile: setup a backup website on Amazon S3 to be served through Cloudfront

The website is more minimal. It also contains media files. On S3, the
configuration is as follows:

 - Enable website hosting
 - Index document: index.html
 - Error document: en/404.html
 - Redirection rules:

<RoutingRules>
    <RoutingRule>
        <Condition>
            <KeyPrefixEquals>fr/</KeyPrefixEquals>
            <HttpErrorCodeReturnedEquals>403</HttpErrorCodeReturnedEquals>
        </Condition>
        <Redirect>
            <ReplaceKeyWith>fr/404.html</ReplaceKeyWith>
        </Redirect>
    </RoutingRule>
</RoutingRules>

 - Permissions, CORS configuration:

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
    <CORSRule>
        <AllowedOrigin>http://vincent.bernat.im</AllowedOrigin>
        <AllowedMethod>GET</AllowedMethod>
        <AllowedMethod>HEAD</AllowedMethod>
    </CORSRule>
</CORSConfiguration>
fabfile: compress resources for S3

There is no "on-the-fly" gzipping on S3/Cloudfront. We also need to
force MIME type since s3cmd does not handle this for us.