Replace bootstrap logic with 'boot.js', use 'component/dart' mime-type and add

pkg/polymer/lib/src/build/mirrors_remover.dart

Index: pkg/polymer/lib/src/build/mirrors_remover.dart
diff --git a/pkg/polymer/lib/src/build/mirrors_remover.dart b/pkg/polymer/lib/src/build/mirrors_remover.dart
index 60b9e2b2d1c05b23e0956c9fb3b34c37d75a2e92..99677bedbaf48307a3f9310ea58a45b3a96f8ccf 100644
--- a/pkg/polymer/lib/src/build/mirrors_remover.dart
+++ b/pkg/polymer/lib/src/build/mirrors_remover.dart
@@ -28,13 +28,9 @@ class MirrorsRemover extends Transformer {
       var end = code.indexOf('show MirrorsUsed;', start);
       if (end == -1) _error();
       end = code.indexOf('\n', end);
-      var loaderImport = code.indexOf(
-          "import 'src/mirror_loader.dart' as loader;", end);
-      if (loaderImport == -1) _error();
       var sb = new StringBuffer()
           ..write(code.substring(0, start))
-          ..write(code.substring(end)
-              .replaceAll('src/mirror_loader.dart', 'src/static_loader.dart'));
+          ..write(code.substring(end));
 
       transform.addOutput(new Asset.fromString(id, sb.toString()));
     });