tell clang-format to use google style for formatting

Previously, one had to create a .clang-format in their home directory or
something for it to work right.

Change-Id: I68afaa7dd68caffab92dca61a639c74fde18b02b
diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..11973e3
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1 @@
+BasedOnStyle: 'google'