Quite an overhaul of the main homepage contents as they were a little out

Quite an overhaul of the main homepage contents as they were a little out
of date (so quickly!).  Put in a lot more links to the important things of
the project - who we are, documents, screenshots etc.  Also added a few of
the screenshots to make the page try and look at least a little bit more
exciting.  Also fixed some badass HTML (! -> ")