Texplay - Ruby 2 and Windows support

Ruby 2 and later needs to use the texplay 0.4.4.pre gem
banister/texplay#22
While this does not compile on windows so we need to use the older gem. Though the version number is not specific this could cause some issues in the future.

metro.gemspec

@@ -25,7 +25,13 @@ Gem::Specification.new do |gem|
   gem.homepage      = Metro::WEBSITE
 
   gem.add_dependency 'gosu', '~> 0.7'
-  gem.add_dependency 'texplay', '~> 0.4'
+
+  if RUBY_PLATFORM == "i386-mingw32"
+    gem.add_dependency 'texplay', '~> 0.4'
+  else
+    gem.add_dependency 'texplay', '~> 0.4.4.pre'
+  end
+
   gem.add_dependency 'chipmunk', '~> 6.1.3.1'
   gem.add_dependency 'tmx', '~> 0.1.2'
   gem.add_dependency 'thor', '~> 0.16.0'