backdrop image for 10.5

[kalxas]

Action item for release

[kalxas]

we also need to update 2 screenshots with the new backdrop

[kalxas]

I am proposing to use the default black backdrop image for this release.

[kalxas]

​https://lists.osgeo.org/pipermail/live-demo/2017-March/011915.html

[kalxas]

I see there is a pull request, so I guess we have concluded with voting?

​https://github.com/OSGeo/OSGeoLive/pull/159

[bakaniko]

For the moment it is the leader and since the release is near, I took the liberty to send this one.

So there is a least one liked backdrop image, if the poll change I'll make another pull request.

Doing this, I hope it gives you the possibility for merging without me being late.

Please consider this as a prepared request :)

[kalxas]

Merged :)