Remove template engines from development dependency:

We're using Bundler for managing dependencies now.

tilt.gemspec

@@ -89,29 +89,6 @@ Gem::Specification.new do |s|
 
   s.executables = ['tilt']
   s.test_files = s.files.select {|path| path =~ /^test\/.*_test.rb/}
-  s.add_development_dependency 'asciidoctor', '>= 0.1.0'
-  s.add_development_dependency 'RedCloth'
-  s.add_development_dependency 'bluecloth'
-  s.add_development_dependency 'builder'
-  s.add_development_dependency 'coffee-script'
-  s.add_development_dependency 'contest'
-  s.add_development_dependency 'creole'
-  s.add_development_dependency 'erubis'
-  s.add_development_dependency 'haml', '>= 2.2.11'
-  s.add_development_dependency 'kramdown'
-  s.add_development_dependency 'less'
-  s.add_development_dependency 'liquid'
-  s.add_development_dependency 'markaby'
-  s.add_development_dependency 'maruku'
-  s.add_development_dependency 'nokogiri'
-  s.add_development_dependency 'radius'
-  s.add_development_dependency 'rdiscount'
-  s.add_development_dependency 'rdoc'
-  s.add_development_dependency 'redcarpet'
-  s.add_development_dependency 'sass'
-  s.add_development_dependency 'wikicloth'
-  s.add_development_dependency 'yajl-ruby'
-  s.add_development_dependency 'rdoc'
 
   s.homepage = "http://github.com/rtomayko/tilt/"
   s.rdoc_options = ["--line-numbers", "--inline-source", "--title", "Tilt", "--main", "Tilt"]