small changes to project dev files

Rakefile

@@ -11,6 +11,7 @@ begin
     gem.homepage = "http://github.com/jimeh/time_ext"
     gem.authors = ["Jim Myhrberg"]
     gem.add_development_dependency "rspec", ">= 1.2.9"
+    gem.add_development_dependency "yard", ">= 0"
     # gem is a Gem::Specification... see http://www.rubygems.org/read/chapter/20 for additional settings
   end
   Jeweler::GemcutterTasks.new
@@ -34,12 +35,11 @@ task :spec => :check_dependencies
 
 task :default => :spec
 
-require 'rake/rdoctask'
-Rake::RDocTask.new do |rdoc|
-  version = File.exist?('VERSION') ? File.read('VERSION') : ""
-
-  rdoc.rdoc_dir = 'rdoc'
-  rdoc.title = "time_ext #{version}"
-  rdoc.rdoc_files.include('README*')
-  rdoc.rdoc_files.include('lib/**/*.rb')
+begin
+  require 'yard'
+  YARD::Rake::YardocTask.new
+rescue LoadError
+  task :yardoc do
+    abort "YARD is not available. In order to run yardoc, you must: sudo gem install yard"
+  end
 end