Add in-tree mspec and ruby/spec

* For easier modifications of ruby/spec by MRI developers.
* .gitignore: track changes under spec.
* spec/mspec, spec/rubyspec: add in-tree mspec and ruby/spec.
  These files can therefore be updated like any other file in MRI.
  Instructions are provided in spec/README.
  [Feature #13156] [ruby-core:79246]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58595 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/rubyspec/core/kernel/puts_spec.rb

@@ -0,0 +1,29 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Kernel#puts" do
+  before :each do
+    @stdout = $stdout
+    @name = tmp("kernel_puts.txt")
+    $stdout = new_io @name
+  end
+
+  after :each do
+    $stdout.close
+    $stdout = @stdout
+    rm_r @name
+  end
+
+  it "is a private method" do
+    Kernel.should have_private_instance_method(:puts)
+  end
+
+  it "delegates to $stdout.puts" do
+    $stdout.should_receive(:puts).with(:arg)
+    puts :arg
+  end
+end
+
+describe "Kernel.puts" do
+  it "needs to be reviewed for spec completeness"
+end