Improve the Asset Loading Screen during initial load

[RoyAwesome]

Currently it just shows a loading bar and some text.

It should have a header image, some text describing the Worldsmith project, linking to the project page and displaying credits.

It could play a little bit of dota music when starting up (akin to how the Warcraft 3 editor played music when starting up), but that is purely optional.

[SinZ163]

using http://youtu.be/ef5AsJl71jk?t=22m56s is a viable option for the sound

[RoyAwesome]

That is a fantastic idea