AssetManager should be able to read a asset 'collection' file.

[GoogleCodeExporter]

When working with a lot of diffrent assets you soon realise how unorganized the 
whole thing is getting.
I noticed while developing a small game, with really not many assets, I ended 
up with 11 images and one font file. If one now would go a step further and 
develop a bigger game there could be hundreds of files.
The best way to resolve this issue is by creating one big file (or you could 
also have multiple files), which contains all the tiny other files.
This could be a simple zip file or a selfwritten binary file.
Such a feature would be great for game development!

Original issue reported on code.google.com by youtube@my-gate.net on 18 Feb 2011 at 12:30