Add missing hasNew.

lib/resolve/Resolver.js

@@ -45,6 +45,10 @@ Resolver.prototype.resolve = function () {
     .then(this._parseJson.bind(this));
 };
 
+Resolver.prototype.hasNew = function (oldResolution) {
+    return Q.resolve(true);
+};
+
 Resolver.prototype.isCacheable = function () {
     return false;
 };

lib/resolve/resolvers/FsResolver.js

@@ -10,11 +10,18 @@ util.inherits(FsResolver, Resolver);
 
 // -----------------
 
+FsResolver.prototype.hasNew = function (oldResolution) {
+    // TODO: should we store latest modified files in the resolution and compare?
+    return Q.resolve(true);
+};
+
 FsResolver.prototype._resolveSelf = function () {
     return this._copy()
     .then(this._extract.bind(this));
 };
 
+// -----------------
+
 FsResolver.prototype._copy = function () {
 
 };

lib/resolve/resolvers/UrlResolver.js

@@ -10,11 +10,18 @@ util.inherits(UrlResolver, Resolver);
 
 // -----------------
 
+UrlResolver.prototype.hasNew = function (oldResolution) {
+    // Store cache expiration headers in the resolution and compare them afterwards
+    Q.resolve(true);
+};
+
 UrlResolver.prototype._resolveSelf = function () {
     return this._download()
     .then(this._extract.bind(this));
 };
 
+// -----------------
+
 UrlResolver.prototype._download = function () {
 
 };