Update .gitignore (dart-lang/watcher#77)

pkgs/watcher/.gitignore

diff --git a/pkgs/watcher/.gitignore b/pkgs/watcher/.gitignore
index 7dbf035..ac98e87 100644
--- a/pkgs/watcher/.gitignore
+++ b/pkgs/watcher/.gitignore
@@ -1,15 +1,4 @@
 # Don’t commit the following directories created by pub.
-.buildlog
-.pub/
-build/
-packages
+.dart_tool
 .packages
-
-# Or the files created by dart2js.
-*.dart.js
-*.js_
-*.js.deps
-*.js.map
-
-# Include when developing application packages.
-pubspec.lock
\ No newline at end of file
+pubspec.lock