Add Stdafx.h headers to fix release win build breaks; add -mavx2 flag to

fix linux build break

Makefile

@@ -68,7 +68,7 @@ INCLUDEPATH:= $(addprefix $(SOURCEDIR)/, Common/Include Math CNTK ActionsLib Com
 # COMMON_FLAGS include settings that are passed both to NVCC and C++ compilers.
 COMMON_FLAGS:= -D_POSIX_SOURCE -D_XOPEN_SOURCE=600 -D__USE_XOPEN2K -std=c++11
 CPPFLAGS:= 
-CXXFLAGS:= -msse3 -std=c++0x -fopenmp -fpermissive -fPIC -Werror -fcheck-new
+CXXFLAGS:= -msse3 -mavx2 -std=c++0x -fopenmp -fpermissive -fPIC -Werror -fcheck-new
 LIBPATH:=
 LIBS:=
 LDFLAGS:=

Source/Math/BlockHandlerAVX.cpp

@@ -2,6 +2,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE.md file in the project root for full licence information.
 //
+#include "stdafx.h"
 #include <malloc.h>
 #include <xmmintrin.h>
 #include <emmintrin.h>

Source/Math/BlockHandlerAVX.h

@@ -105,7 +105,7 @@ class MATH_API BlockHandlerAVX
         {
             return nullptr;
         }
-        static void FreePreparedB(VectorT* freeMe) { assert(nullptr == freeMe); }
+        static void FreePreparedB(VectorT* freeMe) { freeMe;  assert(nullptr == freeMe); }
 };
 
 #define LOADAVX2_128x4 \

Source/Math/BlockHandlerSSE.cpp

@@ -2,6 +2,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE.md file in the project root for full licence information.
 //
+#include "stdafx.h"
 #include <xmmintrin.h>
 #include <emmintrin.h>
 #include <tmmintrin.h>

Source/Math/BlockHandlerSSE.h

@@ -113,7 +113,7 @@ class MATH_API BlockHandlerSSE
             prepareMe;  k; n; //warning re. unreferenced params
             return nullptr;
         }
-        static void FreePreparedB(VectorT* freeMe) { assert(nullptr == freeMe); }
+        static void FreePreparedB(VectorT* freeMe) { freeMe;  assert(nullptr == freeMe); }
 
 };