listObjects: do not do stat during readdir()

* listObjects: improve response time by not doing stat during readDir() operation.

* listObjects: Add windows support.

* listObjects: Readdir() in batches to conserve memory. Add solaris build.

* listObjects: cleanup code.

fs-dirent-fileno.go

@@ -0,0 +1,25 @@
+// +build openbsd netbsd freebsd dragonfly
+
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import "syscall"
+
+func skipDirent(dirent *syscall.Dirent) bool {
+	return dirent.Fileno == 0
+}