Add missing "imports" to the 0.7 tutorial

[igalic]

0.7 does a way with exporting the standard modules from prelude, however its tutorial doesn't add any imports. 206ab89 fixes that and should be "backported".

[huonw]

I believe that 206ab89 is in 0.7, since Github says that it is, and the docs seem to have those changes (no io:: on the println in the code snippet there). Also, note that that commit is actually the commit that removes the re-exports.

Closing; feel free to reopen & clarify if I misunderstand something.

[igalic]

You're right. My bad. The annotations that say use std::float are in 0.7, just as they are in master:

~~~
# use std::float;
fn … {
  let pi = float::consts::pi;
}
~~~

However, they -- or any annotations starting with # are not displayed on the pages. Is that a feature?

[huonw]

It's a bug, I opened #7689. (Some common modules like float used to be in the prelude, and so were imported by default, I guess the documentation wasn't updated in the most user-friendly way.)