clang-format: Enable #include sorting by default.

This has seen quite some usage and I am not aware of any issues. Also
add a style option to enable/disable include sorting. The existing
command line flag can from now on be used to override whatever is set
in the style.

git-svn-id: svn://svn.chromium.org/llvm-project/cfe/trunk/tools/clang-format@253202 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
diff --git a/clang-format.py b/clang-format.py
index 1725e86..5cb41fc 100644
--- a/clang-format.py
+++ b/clang-format.py
@@ -72,7 +72,7 @@
     startupinfo.wShowWindow = subprocess.SW_HIDE
 
   # Call formatter.
-  command = [binary, '-style', style, '-cursor', str(cursor), '-sort-includes']
+  command = [binary, '-style', style, '-cursor', str(cursor)]
   if lines != 'all':
     command.extend(['-lines', lines])
   if fallback_style: