Rename StopWatch to Stopwatch. Add new Stopwatch.start() and Stopwatch.reset().

frog/leg/compiler.dart

Index: frog/leg/compiler.dart
===================================================================
--- frog/leg/compiler.dart	(revision 1504)
+++ frog/leg/compiler.dart	(working copy)
@@ -118,9 +118,9 @@
 
 class CompilerTask {
   final Compiler compiler;
-  final StopWatch watch;
+  final Stopwatch watch;
 
-  CompilerTask(this.compiler) : watch = new StopWatch();
+  CompilerTask(this.compiler) : watch = new Stopwatch();
 
   String get name() => 'Unknown task';
   int get timing() => watch.elapsedInMs();