Rename fletch -> dartino

lib/os/os.dart

 // 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.
 
-library dart.fletch.os;
+library dart.dartino.os;
 
-import 'dart:fletch._system' as fletch;
-import 'dart:fletch';
-import 'dart:fletch.ffi';
+import 'dart:dartino._system' as dartino;
+import 'dart:dartino';
+import 'dart:dartino.ffi';
 
 part 'native_process.dart';
 part 'event_handler.dart';
 
 final ForeignFunction _nanosleep = ForeignLibrary.main.lookup("nanosleep");
 
 class _Timespec extends Struct {
   _Timespec() : super(2);
   int get tv_sec => getField(0);
   int get tv_nsec => getField(1);
   void set tv_sec(int value) => setField(0, value);
   void set tv_nsec(int value) => setField(1, value);
 }
 
 // Sleep is still here and not in package:os, as it is used in async_patch.dart.
 void sleep(int milliseconds) {
   _Timespec timespec = new _Timespec();
   timespec.tv_sec = milliseconds ~/ 1000;
   timespec.tv_nsec = (milliseconds % 1000) * 1000000;
   int result;
   try {
     result = _nanosleep.icall$2Retry(timespec, timespec);
   } finally {
     timespec.free();
   }
   if (result != 0) throw "Failed to call 'nanosleep': ${Foreign.errno}";
 }