fix Psych loading problem

Fix this problem: https://github.com/ruby-opencv/ruby-opencv/pull/6
Thanks for aledalgrande!

Manifest.txt

@@ -110,6 +110,7 @@ ext/opencv/iplconvkernel.h
 ext/opencv/iplimage.cpp
 ext/opencv/iplimage.h
 ext/opencv/lib/opencv.rb
+ext/opencv/lib/opencv/psyched_yaml.rb
 ext/opencv/lib/opencv/version.rb
 ext/opencv/mouseevent.cpp
 ext/opencv/mouseevent.h

Rakefile

@@ -1,14 +1,13 @@
 # -*- ruby -*-
-
 require 'rubygems'
+require './ext/opencv/lib/opencv/psyched_yaml'
 require 'hoe'
-
 require 'rake/extensiontask'
 require './ext/opencv/lib/opencv/version'
 
 Hoe.plugin :gemspec
 
-hoespec = Hoe.spec 'opencv'  do |p|
+hoespec = Hoe.spec 'opencv' do |p|
   p.version = OpenCV::VERSION
   p.changes = p.paragraphs_of('History.txt', 0..1).join("\n\n")
   p.description = <<EOF

ext/opencv/lib/opencv/psyched_yaml.rb

@@ -0,0 +1,22 @@
+# -*- mode: ruby; coding: utf-8-unix -*- 
+# Psych loader for avoiding loading problem
+# (borrowed from Bundler 1.1.rc.7 https://github.com/carlhuda/bundler/blob/v1.1.rc.7/lib/bundler/psyched_yaml.rb )
+#
+# See: https://github.com/ruby-opencv/ruby-opencv/pull/6
+
+# Psych could be a gem
+begin
+  gem 'psych'
+rescue Gem::LoadError
+end if defined?(Gem)
+
+# Psych could be a stdlib
+begin
+  # it's too late if Syck is already loaded
+  require 'psych' unless defined?(Syck)
+rescue LoadError
+end
+
+# Psych might NOT EXIST AT ALL
+require 'yaml'
+