[Live-demo] presentation update

[Barry Rowlingson]

I'm just going through the presentation and comparing with the
software listed here: http://live.osgeo.org/en/overview/overview.html

I've updated a few screenshots to use the ones in the online docs.

I think EOxServer and GEOS are the only things mentioned in the online
docs that aren't in the presentation, so I'll add them. I don't think
anything has been taken away.

Is it worth re-ordering the presentation to exactly match the order in
the online documentation?

Barry