Sidebar links on the website are confusing beginners

[z0w0]

The website's documentation links on the side keep confusing beginners (I've seen this popup a number of times on #rust). They click the tutorial link under documentation thinking it's the same documentation for their version, but instead it's for the latest git master and then they get confused as to why the example code is broken.

[brson]

Let's fix this for 0.4. We can rearrange the documentation links to emphasize the current version.

[brson]

I pushed some changes to rust-lang.org to try to improve the situation. Now we link to the current-release and if you want the bleeding edge you have to chase it down through the wiki.

[brson]

I'm going to call this done. Let me know if there are further improvements I can make.