Merge Pysch 3.0.3.pre1.

  I added the following additional commits from 3.0.3.pre1:
    * https://github.com/ruby/psych/pull/356
    * https://github.com/ruby/psych/pull/357
    * https://github.com/ruby/psych/pull/359

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63280 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 0 deletions

diff --git a/ext/psych/lib/psych/nodes/document.rb b/ext/psych/lib/psych/nodes/document.rb
index 3cd418eaf3..f57410d636 100644
--- a/ext/psych/lib/psych/nodes/document.rb
+++ b/ext/psych/lib/psych/nodes/document.rb
@@ -56,6 +56,8 @@ module Psych
       def root
         children.first
       end
+
+      def document?; true; end
     end
   end
 end