SignatureDB: Add missing license headers

Source/Core/Core/PowerPC/SignatureDB/CSVSignatureDB.cpp

@@ -1,3 +1,7 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
 #include <cstdio>
 #include <fstream>
 #include <sstream>

Source/Core/Core/PowerPC/SignatureDB/CSVSignatureDB.h

@@ -1,3 +1,7 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
 #pragma once
 
 #include "Core/PowerPC/SignatureDB/SignatureDB.h"

Source/Core/Core/PowerPC/SignatureDB/DSYSignatureDB.cpp

@@ -1,3 +1,7 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
 #include <cstddef>
 #include <cstring>
 

Source/Core/Core/PowerPC/SignatureDB/DSYSignatureDB.h

@@ -1,3 +1,7 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
 #pragma once
 
 #include "Core/PowerPC/SignatureDB/SignatureDB.h"