Updated gem dependencies

* Use exact match for dm-core dep.  Will hopefully prevent version
  mismatch problems since every plugin must be at the same version.
* Updated deps for gems to latest stable versions
* Fixed failing specs for ruby 1.9.1

Rakefile

@@ -12,7 +12,7 @@ AUTHOR = 'Guy van den Berg'
 EMAIL  = 'vandenberg.guy [a] gmail [d] com'
 GEM_NAME = 'dm-serializer'
 GEM_VERSION = DataMapper::Serializer::VERSION
-GEM_DEPENDENCIES = [['dm-core', "~>#{GEM_VERSION}"]]
+GEM_DEPENDENCIES = [['dm-core', GEM_VERSION]]
 GEM_CLEAN = %w[ log pkg coverage ]
 GEM_EXTRAS = { :has_rdoc => true, :extra_rdoc_files => %w[ README.textile LICENSE TODO History.txt ] }
 

benchmarks/to_xml.rb

@@ -1,7 +1,7 @@
 require "rubygems"
 require 'pathname'
 
-gem 'dm-core', '~>0.9.11'
+gem 'dm-core', '0.9.11'
 require 'dm-core'
 
 spec_dir_path = Pathname(__FILE__).dirname.expand_path

spec/public/to_xml_spec.rb

@@ -62,7 +62,7 @@ def cast(value, type)
     it "should not include the XML prologue, so that the result can be embedded in other XML documents" do
       planet = Planet.new
       xml = planet.to_xml(:element_name => "aplanet")
-      xml.starts_with?("<?xml").should == false
+      xml.should_not =~ /\A<\?xml/
     end
 
     describe ':element_name option for Resource' do

spec/spec_helper.rb

@@ -1,7 +1,7 @@
 require 'pathname'
 require 'rubygems'
 
-gem 'dm-core', '~>0.9.11'
+gem 'dm-core', '0.9.11'
 require 'dm-core'
 
 spec_dir_path = Pathname(__FILE__).dirname.expand_path

tasks/spec.rb

@@ -1,5 +1,5 @@
 begin
-  gem 'rspec', '~>1.1.11'
+  gem 'rspec', '~>1.2'
   require 'spec'
   require 'spec/rake/spectask'