Rename fletch -> dartino

src/vm/pair.h

 // Copyright (c) 2015, the Dartino project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE.md file.
 
 #ifndef SRC_VM_PAIR_H_
 #define SRC_VM_PAIR_H_
 
-namespace fletch {
+namespace dartino {
 
 // Basically the same as a std::pair, but we don't want to rely on that
 // being present on a given platform.
 template <typename First, typename Second>
 class Pair {
  public:
   Pair(First f, Second s) : first(f), second(s) {}
 
   First first;
   Second second;
 };
 
-}  // namespace fletch
+}  // namespace dartino
 
 #endif  // SRC_VM_PAIR_H_