Replace arrays.some with Array.prototype.some

See #441.

lib/compiler/asts.js

@@ -32,7 +32,7 @@ var asts = {
       action: consumesExpression,
 
       sequence: function(node) {
-        return arrays.some(node.elements, consumes);
+        return node.elements.some(consumes);
       },
 
       labeled:      consumesExpression,

lib/utils/arrays.js

@@ -58,18 +58,6 @@ var arrays = {
 
   pluck: function(array, key) {
     return array.map(function (e) { return e[key]; });
-  },
-
-  some: function(array, predicate) {
-    var length = array.length, i;
-
-    for (i = 0; i < length; i++) {
-      if (predicate(array[i])) {
-        return true;
-      }
-    }
-
-    return false;
   }
 };