changes to stdout and -err - tests and behaviour

By using $stdin adn $stderr instead of STDIN and 
STDERR it is possible to capture or redirect them 
using in process ruby code without the need
to manage pipes and external processes

lib/jekyll.rb

@@ -67,10 +67,10 @@ module Jekyll
     begin
       config = YAML.load_file(config_file)
       raise "Invalid configuration - #{config_file}" if !config.is_a?(Hash)
-      STDOUT.puts "Configuration from #{config_file}"
+      $stdout.puts "Configuration from #{config_file}"
     rescue => err
-      STDERR.puts "WARNING: Could not read configuration. Using defaults (and options)."
-      STDERR.puts "\t" + err.to_s
+      $stderr.puts "WARNING: Could not read configuration. Using defaults (and options)."
+      $stderr.puts "\t" + err.to_s
       config = {}
     end
 

test/test_configuration.rb

@@ -8,21 +8,21 @@ class TestConfiguration < Test::Unit::TestCase
 
     should "fire warning with no _config.yml" do
       mock(YAML).load_file(@path) { raise "No such file or directory - #{@path}" }
-      mock(STDERR).puts("WARNING: Could not read configuration. Using defaults (and options).")
-      mock(STDERR).puts("\tNo such file or directory - #{@path}")
+      mock($stderr).puts("WARNING: Could not read configuration. Using defaults (and options).")
+      mock($stderr).puts("\tNo such file or directory - #{@path}")
       assert_equal Jekyll::DEFAULTS, Jekyll.configuration({})
     end
 
     should "load configuration as hash" do
       mock(YAML).load_file(@path) { Hash.new }
-      mock(STDOUT).puts("Configuration from #{@path}")
+      mock($stdout).puts("Configuration from #{@path}")
       assert_equal Jekyll::DEFAULTS, Jekyll.configuration({})
     end
 
     should "fire warning with bad config" do
       mock(YAML).load_file(@path) { Array.new }
-      mock(STDERR).puts("WARNING: Could not read configuration. Using defaults (and options).")
-      mock(STDERR).puts("\tInvalid configuration - #{@path}")
+      mock($stderr).puts("WARNING: Could not read configuration. Using defaults (and options).")
+      mock($stderr).puts("\tInvalid configuration - #{@path}")
       assert_equal Jekyll::DEFAULTS, Jekyll.configuration({})
     end
   end