Merge changes from topic "windows-support"

* changes:
  Port os.rename calls to work on Windows
  Workaround shutil.rmtree limitation on Windows
  Add support for creating symbolic links on Windows
  Make "git command" and "forall" work on Windows

subcmds/init.py

@@ -17,7 +17,6 @@ from __future__ import print_function
 import os
 import platform
 import re
-import shutil
 import sys
 
 from pyversion import is_python3
@@ -35,6 +34,7 @@ from error import ManifestParseError
 from project import SyncBuffer
 from git_config import GitConfig
 from git_command import git_require, MIN_GIT_VERSION
+import platform_utils
 
 class Init(InteractiveCommand, MirrorSafeCommand):
   common = True
@@ -252,7 +252,7 @@ to update the working directory files.
       # Better delete the manifest git dir if we created it; otherwise next
       # time (when user fixes problems) we won't go through the "is_new" logic.
       if is_new:
-        shutil.rmtree(m.gitdir)
+        platform_utils.rmtree(m.gitdir)
       sys.exit(1)
 
     if opt.manifest_branch: