Add a .clang-format file.

This isn't meant to be authoritative. It's good enough to let the
"indent current line using clang-format" hotkey do the right thing often
enough to be useful.

.clang-format

@@ -0,0 +1,25 @@
+# Copyright 2014 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This isn't meant to be authoritative, but it's good enough to be useful.
+# Still use your best judgement for formatting decisions: clang-format
+# sometimes makes strange choices.
+
+BasedOnStyle: Google
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+Cpp11BracedListStyle: false
+IndentCaseLabels: false