Ruby 1.9 compatibility

* Adds current directory to load path for tests because 1.9 does not
* Aliases String#lines to String#to_a under 1.8 to match 1.9 behavior
* Sets encoding magic comment in test file with characters outside ascii
* Require 'ostruct' explicitly

This depends on a patch to Grit to have full functionality through the
whole stack.

Rakefile

@@ -47,7 +47,7 @@ task :default => :test
 
 require 'rake/testtask'
 Rake::TestTask.new(:test) do |test|
-  test.libs << 'lib' << 'test'
+  test.libs << 'lib' << 'test' << '.'
   test.pattern = 'test/**/test_*.rb'
   test.verbose = true
 end
@@ -143,4 +143,4 @@ task :validate do
     puts "A `VERSION` file at root level violates Gem best practices."
     exit!
   end
-end
+end