Fixes for the windows archives (#22)

* add file extension for windows executables

* fix comments

package/dart-sass.bat

@@ -1,11 +1,11 @@
 @echo off
-%REM Copyright 2016 Google Inc. Use of this source code is governed by an
-%REM MIT-style license that can be found in the LICENSE file or at
-%REM https://opensource.org/licenses/MIT.
+REM Copyright 2016 Google Inc. Use of this source code is governed by an
+REM MIT-style license that can be found in the LICENSE file or at
+REM https://opensource.org/licenses/MIT.
 
-%REM This script drives the standalone Sass package, which bundles together a
-%REM Dart executable and a snapshot of Sass. It can be created with `pub run
-%REM grinder package`.
+REM This script drives the standalone Sass package, which bundles together a
+REM Dart executable and a snapshot of Sass. It can be created with `pub run
+REM grinder package`.
 
 set SCRIPTPATH=%~dp0
 set arguments=%*

tool/grind.dart

@@ -116,7 +116,9 @@ Future _buildPackage(http.Client client, String os, String architecture) async {
   var sassLicense = new File('LICENSE').readAsBytesSync();
   var dartLicense = new File(p.join(_sdkDir, 'LICENSE')).readAsBytesSync();
   var archive = new Archive()
-    ..addFile(_file("dart-sass/src/dart", executable, executable: true))
+    ..addFile(_file(
+        "dart-sass/src/dart${os == 'windows' ? '.exe' : ''}", executable,
+        executable: true))
     ..addFile(_file("dart-sass/src/DART_LICENSE", dartLicense))
     ..addFile(_file("dart-sass/src/sass.dart.snapshot", snapshot))
     ..addFile(_file("dart-sass/src/SASS_LICENSE", sassLicense))