Added cgi_escape filter

lib/jekyll/filters.rb

@@ -21,6 +21,10 @@ module Jekyll
       input.gsub("&", "&amp;").gsub("<", "&lt;").gsub(">", "&gt;")
     end
 
+    def cgi_escape(input)
+      CGI::escape(input)
+    end
+
     def number_of_words(input)
       input.split.length
     end

test/test_filters.rb

@@ -37,5 +37,13 @@ class TestFilters < Test::Unit::TestCase
       assert_equal "AT&amp;T", @filter.xml_escape("AT&T")
       assert_equal "&lt;code&gt;command &amp;lt;filename&amp;gt;&lt;/code&gt;", @filter.xml_escape("<code>command &lt;filename&gt;</code>")
     end
+
+    should "escape space as plus" do
+      assert_equal "my+things", @filter.cgi_escape("my things")
+    end
+
+    should "escape special characters" do
+      assert_equal "hey%21", @filter.cgi_escape("hey!")
+    end
   end
 end