Gut the box[m][o] family from util.

src/lib/util.rs

@@ -1,8 +1,4 @@
 type option[T] = tag(none(), some(T));
-type box[T] = tup(@T);
-type boxo[T] = option[box[T]];
-type boxm[T] = tup(mutable @T);
-type boxmo[T] = option[boxm[T]];
 
 type map[T, U] = fn(&T) -> U;
 
@@ -17,28 +13,6 @@ fn option_map[T, U](map[T, U] f, &option[T] opt) -> option[U] {
   }
 }
 
-fn unbox[T](&box[T] b) -> T {
-  ret b._0;
-}
-
-
-fn unboxm[T](&boxm[T] b) -> T {
-  ret b._0;
-}
-
-fn unboxo[T](boxo[T] b) -> option[T] {
-  // Pending issue #90, no need to alias the function item in order to pass
-  // it as an arg.
-  let map[box[T], T] f = unbox[T];
-  be option_map[box[T], T](f, b);
-}
-
-fn unboxmo[T](boxmo[T] b) -> option[T] {
-  // Issue #90, as above
-  let map[boxm[T], T] f = unboxm[T];
-  be option_map[boxm[T], T](f, b);
-}
-
 fn id[T](T x) -> T {
   ret x;
 }