auto merge of #7474 : Seldaek/rust/clean-iter, r=thestinger

I think it's WIP - but I wanted to ask for feedback (/cc @thestinger)

I had to move the impl of FromIter for vec into extra::iter because I don't think std can depend on extra, but that's a bit messed up. Similarly some FromIter uses are gone now, not sure if this is fixable or if I made a complete mess here..

src/libstd/vec.rs

@@ -19,7 +19,6 @@ use cmp;
 use cmp::{Eq, Ord, TotalEq, TotalOrd, Ordering, Less, Equal, Greater};
 use clone::Clone;
 use iterator::{FromIterator, Iterator, IteratorUtil};
-use iter::FromIter;
 use kinds::Copy;
 use libc;
 use libc::c_void;
@@ -2168,15 +2167,6 @@ pub struct VecMutRevIterator<'self, T> {
 }
 iterator!{impl VecMutRevIterator -> &'self mut T, -1}
 
-impl<T> FromIter<T> for ~[T]{
-    #[inline]
-    pub fn from_iter(iter: &fn(f: &fn(T) -> bool) -> bool) -> ~[T] {
-        let mut v = ~[];
-        for iter |x| { v.push(x) }
-        v
-    }
-}
-
 #[cfg(stage0)]
 impl<A, T: Iterator<A>> FromIterator<A, T> for ~[A] {
     pub fn from_iterator(iterator: &mut T) -> ~[A] {