switch html5lib to new pkg layout

lib/html5parser.dart

Index: lib/html5parser.dart
diff --git a/html5parser.dart b/lib/html5parser.dart
similarity index 99%
rename from html5parser.dart
rename to lib/html5parser.dart
index a0e18d291047f421e08e7bfbfa77bc59ff74a567..e95ded98132b48eade043f97f6a008622b0459de 100644
--- a/html5parser.dart
+++ b/lib/html5parser.dart
@@ -2,19 +2,21 @@
 
 #import('dart:math');
 #import('package:logging/logging.dart');
-#import('treebuilders/base.dart'); // for Marker
-#import('treebuilders/simpletree.dart');
-#import('lib/constants.dart');
-#import('lib/encoding_parser.dart');
-#import('lib/token.dart');
-#import('lib/utils.dart');
+#import('src/treebuilder.dart');
+#import('src/constants.dart');
+#import('src/encoding_parser.dart');
+#import('src/token.dart');
+#import('src/utils.dart');
 #import('tokenizer.dart');
+#import('dom.dart');
 
 // TODO(jmesserly): these APIs, as well as the HTMLParser contructor and
 // HTMLParser.parse and parseFragment were changed a bit to avoid passing a
 // first class type that is used for construction. It might be okay, but I'd
 // like to find a good dependency-injection pattern for Dart rather than
 // copy the Python API.
+// TODO(jmesserly): right now HTMLParser.parse API exposes tokenizer, which
+// means tokenizer itself is public. Ideally that would not be the case.
 // TODO(jmesserly): Also some of the HTMLParser APIs are messed up to avoid
 // editor shadowing warnings :\. Look for trailing underscores.
 /**