Fixed a strange error in some cases

error loading "/Users/k-sera/test/gems/sdoc-0.3.20/lib/rdoc/discover.rb": uninitialized constant RDoc::Generator (NameError)
/Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rdoc.rb:101:in `const_missing': uninitialized constant RDoc::Generator (NameError)
        from /Users/k-sera/test/gems/rdoc-3.12.2/lib/rdoc/generator/markup.rb:8:in `<top (required)>'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from /Users/k-sera/test/gems/rdoc-3.12.2/lib/rdoc/generator/darkfish.rb:6:in `<top (required)>'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rdoc/rdoc.rb:518:in `<top (required)>'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
        from /Users/k-sera/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
version 0.1.3
Added coveralls