Remove Curl class from CurlBuilder.

lib/CurlBuilder.js

@@ -35,7 +35,6 @@
       curl = function() {
         return curl.perform.apply(curl, arguments);
       };
-      curl.Curl = Curl;
       curl.perform = function() {
         var args, c, cb, k, length, v, _ref, _ref1, _ref2, _ref3, _ref4;
         args = 1 <= arguments.length ? __slice.call(arguments, 0) : [];

lib/CurlBuilder.toffee

@@ -16,7 +16,6 @@ class CurlBuilder
     curl = ->
       curl.perform.apply curl, arguments
 
-    curl.Curl = Curl
     curl.perform = (args...) ->
       if @running
         throw new Error 'the cURL session is busy, use curl.create to create another cURL Session'