Enable clang-format on AOSP Music Player

* Formatted all java code using:
  clang-format -i --style=file src/com/android/music/*.java
* Add clang-format file
* Add PREUPLOAD to check newly uploaded code

Test: mm -j 40
Change-Id: I202b98b29789fc10ad0b11da0c37f6aa0291131c
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
new file mode 100644
index 0000000..7fb1636
--- /dev/null
+++ b/PREUPLOAD.cfg
@@ -0,0 +1,6 @@
+[Options]
+ignore_merged_commits = true
+
+[Builtin Hooks]
+clang_format = true
+