Revert "Fixes dart-lang/markdowndart-lang/markdown#86." This change breaks the CommonMark tests

diff --git a/pkgs/markdown/lib/src/html_renderer.dart b/pkgs/markdown/lib/src/html_renderer.dart
index 03977ca..184f9f9 100644
--- a/pkgs/markdown/lib/src/html_renderer.dart
+++ b/pkgs/markdown/lib/src/html_renderer.dart

@@ -85,11 +85,6 @@
     if (element.isEmpty) {
       // Empty element like <hr/>.
       buffer.write(' />');
-
-      if (element.tag == 'br') {
-        buffer.write('\n');
-      }
-
       return false;
     } else {
       buffer.write('>');

diff --git a/pkgs/markdown/lib/src/inline_parser.dart b/pkgs/markdown/lib/src/inline_parser.dart
index 6a70cc1..9be8704 100644
--- a/pkgs/markdown/lib/src/inline_parser.dart
+++ b/pkgs/markdown/lib/src/inline_parser.dart

@@ -14,7 +14,6 @@
   static final List<InlineSyntax> _defaultSyntaxes =
       new List<InlineSyntax>.unmodifiable(<InlineSyntax>[
     new AutolinkSyntax(),
-    new LineBreakSyntax(),
     new LinkSyntax(),
     new ImageSyntax(),
     // Allow any punctuation to be escaped.
@@ -30,6 +29,10 @@
     new TextSyntax(r'&', sub: '&amp;'),
     // Encode "<". (Why not encode ">" too? Gruber is toying with us.)
     new TextSyntax(r'<', sub: '&lt;'),
+    // Escaped newlines become hard line breaks.
+    new TextSyntax(r'\\\n', sub: '<br />\n'),
+    // Two or more spaces at the end of a line become hard line breaks.
+    new TextSyntax(r'  +\n', sub: '<br />\n'),
     // Parse "**strong**" tags.
     new TagSyntax(r'\*\*', tag: 'strong'),
     // Parse "__strong__" tags.
@@ -188,17 +191,6 @@
   bool onMatch(InlineParser parser, Match match);
 }
 
-/// Represents a hard line break.
-class LineBreakSyntax extends InlineSyntax {
-  LineBreakSyntax() : super(r'(?:\\|  +)\n');
-
-  /// Create a void <br> element.
-  bool onMatch(InlineParser parser, Match match) {
-    parser.addNode(new Element.empty('br'));
-    return true;
-  }
-}
-
 /// Matches stuff that should just be passed through as straight text.
 class TextSyntax extends InlineSyntax {
   final String substitute;