Add Wikipedia Pagecounts example.

Merged feature/wikipedia-example branch.

Squashed commit of the following:

commit 56759bc4d8c30b574a164b96250c0e3f86417058
Author: Santiago M. Mola <smola@stratio.com>
Date:   Wed Dec 3 17:14:28 2014 +0100

    Remove default flume-conf.properties.

commit 5d72d357888bd577c16a37ce2bd08b1e35fe2596
Author: Santiago M. Mola <smola@stratio.com>
Date:   Tue Dec 2 18:17:39 2014 +0100

    examples: Add Kibana dashboard for Wikipedia demo.

commit b2b936d4452c2d9835d0d6640cf7bee6348aace6
Author: Santiago M. Mola <smola@stratio.com>
Date:   Tue Dec 2 17:59:31 2014 +0100

    examples: Add Docker and Fig instructions.

commit 9c92f5cfed973ef65ab196497318b784032021b5
Author: Santiago M. Mola <smola@stratio.com>
Date:   Tue Dec 2 16:53:46 2014 +0100

    demos: Add Docker/fig support for Wikipedia demo.

commit 663ea69744c8323896886e005cfe549837762714
Author: Santiago M. Mola <smola@stratio.com>
Date:   Thu Jul 10 09:47:29 2014 +0200

    Wikipedia pagecounts demo.
Add sandbox provisioning script.
sandbox: Add welcome message; use /bin/bash
sandbox: Add Apache 2 server and fix Kibana dashboards install.
Fix sandbox dashboards.
sandbox: Install examples.