vec: convert append and append_one to methods

These were only free functions on `~[T]` because taking self by-value
used to be broken.

src/test/bench/core-std.rs

@@ -92,7 +92,7 @@ fn vec_plus() {
         if r.gen() {
             v.push_all_move(rv);
         } else {
-            v = vec::append(rv.clone(), v.as_slice());
+            v = rv.clone().append(v.as_slice());
         }
         i += 1;
     }
@@ -106,10 +106,10 @@ fn vec_append() {
     while i < 1500 {
         let rv = Vec::from_elem(r.gen_range(0u, i + 1), i);
         if r.gen() {
-            v = vec::append(v.clone(), rv.as_slice());
+            v = v.clone().append(rv.as_slice());
         }
         else {
-            v = vec::append(rv.clone(), v.as_slice());
+            v = rv.clone().append(v.as_slice());
         }
         i += 1;
     }

src/test/bench/shootout-k-nucleotide-pipes.rs

@@ -126,8 +126,7 @@ fn make_sequence_processor(sz: uint,
       line = from_parent.recv();
       if line == Vec::new() { break; }
 
-       carry = windows_with_carry(vec::append(carry,
-                                                 line.as_slice()).as_slice(),
+       carry = windows_with_carry(carry.append(line.as_slice()).as_slice(),
                                   sz,
                                   |window| {
          update_freq(&mut freqs, window);

src/test/bench/task-perf-alloc-unwind.rs

@@ -97,8 +97,7 @@ fn recurse_or_fail(depth: int, st: Option<State>) {
                 unique: ~Cons((), @*st.unique),
                 tuple: (@Cons((), st.tuple.ref0().clone()),
                         ~Cons((), @*st.tuple.ref1().clone())),
-                vec: vec::append(st.vec.clone(),
-                     &[@Cons((), *st.vec.last().unwrap())]),
+                vec: st.vec.clone().append(&[@Cons((), *st.vec.last().unwrap())]),
                 res: r(@Cons((), st.res._l))
             }
           }

src/test/run-fail/unwind-misc-1.rs

@@ -24,7 +24,7 @@ fn main() {
     for _i in range(0u, 10u) {
         arr.push(@~"key stuff");
         map.insert(arr.clone(),
-                   vec::append(arr.clone(), &[@~"value stuff"]));
+                   arr.clone().append([@~"value stuff"]));
         if arr.len() == 5 {
             fail!();
         }

src/test/run-pass/vec-concat.rs

@@ -13,7 +13,7 @@ use std::vec;
 pub fn main() {
     let a: Vec<int> = vec!(1, 2, 3, 4, 5);
     let b: Vec<int> = vec!(6, 7, 8, 9, 0);
-    let v: Vec<int> = vec::append(a, b.as_slice());
+    let v: Vec<int> = a.append(b.as_slice());
     println!("{}", *v.get(9));
     assert_eq!(*v.get(0), 1);
     assert_eq!(*v.get(7), 8);