Wiki is out of date

[tomsik68]

Incomplete list of things to update:

• move pages explaining non-existing services & concepts (i.e. assets.minecraft.net, pre-1.6 launcher related stuff) somewhere out of the way to simplify wiki structure
• versions.json --> version_manifest.json
• Update extended version information
• structure of libraries
• structure of assets

Feel free to comment on this issue to report more missing/out-of-date parts.