Keep all file names lower case.

Signed-off-by: John McCutchan <john@johnmccutchan.com>
diff --git a/lib/src/BenchmarkBase.dart b/lib/src/benchmark_base.dart
similarity index 98%
rename from lib/src/BenchmarkBase.dart
rename to lib/src/benchmark_base.dart
index d5ce879..9368e5a 100644
--- a/lib/src/BenchmarkBase.dart
+++ b/lib/src/benchmark_base.dart
@@ -1,4 +1,5 @@
 // Copyright 2011 Google Inc. All Rights Reserved.
+// BenchmarkBase.dart
 
 class BenchmarkBase {
   final String name;