Add license header for Minio modifications, improvements for sha1,sha256,sha512 implementations

Also bring in SSE3 optimized public domain implementation of SHA1 from Intel ``FIPS PUB 180-1``

pkg/utils/crypto/sha512/sha512_gen.go

@@ -1,5 +1,21 @@
 // +build ignore
 
+//
+// Mini Object Storage, (C) 2015 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 (