Full restructure in accordance with

- pkg/{subsystem}/{package} style
  - modify Makefile to reflect the new style,
    consolidate various entries
  - add a dummy ``main.go`` at top level

pkg/utils/cpu/cpu.go

@@ -0,0 +1,36 @@
+/*
+ * Mini Object Storage, (C) 2014 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.
+ */
+
+// +build amd64
+
+package cpu
+
+// int has_sse41 (void);
+// int has_avx (void);
+// int has_avx2 (void);
+import "C"
+
+func HasSSE41() bool {
+	return int(C.has_sse41()) == 1
+}
+
+func HasAVX() bool {
+	return int(C.has_avx()) == 1
+}
+
+func HasAVX2() bool {
+	return int(C.has_avx2()) == 1
+}