added the ability to set a host's host to false, causing the urls it creates to be relative

src/lib/host.js

@@ -135,7 +135,11 @@ Host.prototype.makeUrl = function (params) {
     auth = this.auth + '@';
   }
 
-  return this.protocol + '://' + auth + this.host + port + path + (query ? '?' + query : '');
+  if (this.host) {
+    return this.protocol + '://' + auth + this.host + port + path + (query ? '?' + query : '');
+  } else {
+    return path + (query ? '?' + query : '');
+  }
 };
 
 Host.prototype.toString = function () {

test/unit/test_host.js

@@ -149,6 +149,16 @@ describe('Host class', function () {
       host = new Host({ host: 'italy', path: '/pie', auth: 'user:pass'});
       expect(host.makeUrl()).to.be('http://user:pass@italy:9200/pie');
     });
+
+    it('outputs valid relative urls when the host is empty', function () {
+      var host = new Host({
+        host: false,
+        path: '/path',
+        query: { this: 'that' }
+      });
+
+      expect(host + '').to.be('/path?this=that');
+    });
   });
 
   describe('#toString', function () {