fixes #216, JSNumber members

lib/runtime/dart/core.js

 dart.library('dart/core', null, /* Imports */[
 ], /* Lazy imports */[
   'dart/_js_helper',
   'dart/_internal',
   'dart/collection',
   'dart/_interceptors',
   'dart/convert'
 ], function(exports, _js_helper, _internal, collection, _interceptors, convert) {
   'use strict';
   class Object {
@@ skipping 50 matching lines @@
   let deprecated = dart.const(new Deprecated("next release"));
   let override = dart.const(new _Override());
   class _Proxy extends Object {
     _Proxy() {
     }
   }
   dart.setSignature(_Proxy, {
     constructors: () => ({_Proxy: [_Proxy, []]})
   });
   let proxy = dart.const(new _Proxy());
+  dart.defineExtensionNames([
+    'toString'
+  ]);
   class bool extends Object {
     static fromEnvironment(name, opts) {
       let defaultValue = opts && 'defaultValue' in opts ? opts.defaultValue : false;
       throw new UnsupportedError('bool.fromEnvironment can only be used as a const constructor');
     }
     [dartx.toString]() {
       return this ? "true" : "false";
     }
   }
   dart.setSignature(bool, {
@@ skipping 1166 matching lines @@
     constructors: () => ({fromEnvironment: [int, [String], {defaultValue: int}]}),
     statics: () => ({parse: [int, [String], {radix: int, onError: dart.functionType(int, [String])}]}),
     names: ['parse']
   });
   class Invocation extends Object {
     get isAccessor() {
       return dart.notNull(this.isGetter) || dart.notNull(this.isSetter);
     }
   }
   let Iterable$ = dart.generic(function(E) {
+    dart.defineExtensionNames([
+      'join'
+    ]);
     class Iterable extends Object {
       Iterable() {
       }
       static generate(count, generator) {
         if (generator === void 0)
           generator = null;
         if (dart.notNull(count) <= 0)
           return new (_internal.EmptyIterable$(E))();
         return new (exports._GeneratorIterable$(E))(count, generator);
       }
@@ skipping 2091 matching lines @@
   exports.StackTrace = StackTrace;
   exports.Stopwatch = Stopwatch;
   exports.String = String;
   exports.RuneIterator = RuneIterator;
   exports.StringBuffer = StringBuffer;
   exports.StringSink = StringSink;
   exports.Symbol = Symbol;
   exports.Type = Type;
   exports.Uri = Uri;
 });