Removed Cliver as a dependency.

Since I'm not using any Ragel version specific features it's not really needed
to check for the version.

oga.gemspec

@@ -25,7 +25,6 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'racc'
 
-  s.add_development_dependency 'cliver'
   s.add_development_dependency 'rake'
   s.add_development_dependency 'rspec'
   s.add_development_dependency 'yard'

task/lexer.rake

@@ -1,6 +1,4 @@
 rule '.rb' => '.rl' do |task|
-  Cliver.assert('ragel', '~> 6.7')
-
   sh "ragel -F1 -R #{task.source} -o #{task.name}"
 
   puts "Applying patch http://git.io/ow6e1A to #{task.name}"
@@ -19,8 +17,6 @@ rule '.rb' => '.rl' do |task|
 end
 
 rule '.c' => '.rl' do |task|
-  Cliver.assert('ragel', '~> 6.7')
-
   sh "ragel -C -G2 #{task.source} -o #{task.name}"
 end