std: Clean out #[deprecated] APIs

This commit cleans out a large amount of deprecated APIs from the standard
library and some of the facade crates as well, updating all users in the
compiler and in tests as it goes along.

src/doc/reference.md

@@ -977,7 +977,6 @@ An example of `use` declarations:
 
 ```
 # #![feature(core)]
-use std::iter::range_step;
 use std::option::Option::{Some, None};
 use std::collections::hash_map::{self, HashMap};
 
@@ -985,9 +984,6 @@ fn foo<T>(_: T){}
 fn bar(map1: HashMap<String, usize>, map2: hash_map::HashMap<String, usize>){}
 
 fn main() {
-    // Equivalent to 'std::iter::range_step(0, 10, 2);'
-    range_step(0, 10, 2);
-
     // Equivalent to 'foo(vec![std::option::Option::Some(1.0f64),
     // std::option::Option::None]);'
     foo(vec![Some(1.0f64), None]);

src/doc/trpl/iterators.md

@@ -243,11 +243,12 @@ for num in nums.iter() {
 ```
 
 These two basic iterators should serve you well. There are some more
-advanced iterators, including ones that are infinite. Like `count`:
+advanced iterators, including ones that are infinite. Like using range syntax
+and `step_by`:
 
 ```rust
-# #![feature(core)]
-std::iter::count(1, 5);
+# #![feature(step_by)]
+(1..).step_by(5);
 ```
 
 This iterator counts up from one, adding five each time. It will give
@@ -292,11 +293,11 @@ just use `for` instead.
 There are tons of interesting iterator adapters. `take(n)` will return an
 iterator over the next `n` elements of the original iterator, note that this
 has no side effect on the original iterator. Let's try it out with our infinite
-iterator from before, `count()`:
+iterator from before:
 
 ```rust
-# #![feature(core)]
-for i in std::iter::count(1, 5).take(5) {
+# #![feature(step_by)]
+for i in (1..).step_by(5).take(5) {
     println!("{}", i);
 }
 ```