_CPJavaScriptArray -objectsAtIndexes: implementation.

Added speed test in CPArrayPerformanceTest (6x faster).

Foundation/CPArray/_CPJavaScriptArray.j

@@ -120,6 +120,29 @@ var concat = Array.prototype.concat,
     return self[anIndex];
 }
 
+- (CPArray)objectsAtIndexes:(CPIndexSet)indexes
+{
+    if ([indexes lastIndex] >= self.length)
+        [CPException raise:CPRangeException reason:_cmd + " indexes out of bounds"];
+
+    var ranges = indexes._ranges,
+        count  = ranges.length,
+        result = [],
+             i = 0;
+
+    for (; i < count; i++)
+    {
+        var range = ranges[i],
+            loc = range.location,
+            len = range.length,
+            subArray = self.slice(loc, loc + len);
+
+        result.splice.apply(result, [result.length, 0].concat(subArray));
+    }
+
+    return result;
+}
+
 - (CPUInteger)indexOfObject:(id)anObject inRange:(CPRange)aRange
 {
     // Only use isEqual: if our object is a CPObject.