make sure to bind target methods to the target itself in the proxy, add test for session.clear()

lib/cookie-session.js

@@ -37,8 +37,8 @@ Session.prototype = {
 
     // all values from content except special values
     sessionHandler.get = function(rcvr, name) {
-      if (['clear', 'setExpires'].indexOf(name) > -1)
-        return this.target[name];
+      if (['clear', 'setExpires', 'updateCookie'].indexOf(name) > -1)
+        return this.target[name].bind(this.target);
       else
         return this.target.content[name];
     };

test/all-test.js

@@ -43,6 +43,11 @@ suite.addBatch({
     "session object stores and retrieves values properly": function(err, req) {
       req.session.foo = 'bar';
       assert.equal(req.session.foo, 'bar');
+    },
+    "set variables and clear them yields no variables": function(err, req) {
+      req.session.bar = 'baz';
+      req.session.clear();
+      assert.isUndefined(req.session.bar);
     }
   }
 });