Remove the "last changed" version information from source comments
diff --git a/Makefile.am b/Makefile.am
index e4d08b5..b2d2b6a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,7 @@
 # Makefile.am, the source file for Makefile.in (and hence Makefile), is
 #
+# Copyright (c) 2018 Cosmin Truta
 # Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.25 [September 1, 2016]
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
diff --git a/arm/arm_init.c b/arm/arm_init.c
index 02df812..a34ecdb 100644
--- a/arm/arm_init.c
+++ b/arm/arm_init.c
@@ -1,14 +1,15 @@
 
 /* arm_init.c - NEON optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.22 [May 26, 2016]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
+
 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
  * called.
  */
diff --git a/arm/filter_neon.S b/arm/filter_neon.S
index 000764c..2308aad 100644
--- a/arm/filter_neon.S
+++ b/arm/filter_neon.S
@@ -1,9 +1,9 @@
 
 /* filter_neon.S - NEON optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2014,2017 Glenn Randers-Pehrson
  * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.31 [July 27, 2017]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
diff --git a/arm/filter_neon_intrinsics.c b/arm/filter_neon_intrinsics.c
index 75399f6..553c0be 100644
--- a/arm/filter_neon_intrinsics.c
+++ b/arm/filter_neon_intrinsics.c
@@ -1,12 +1,11 @@
 
 /* filter_neon_intrinsics.c - NEON optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
  * Written by James Yu <james.yu at linaro.org>, October 2013.
  * Based on filter_neon.S, written by Mans Rullgard, 2011.
  *
- * Last changed in libpng 1.6.22 [May 26, 2016]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
diff --git a/intel/filter_sse2_intrinsics.c b/intel/filter_sse2_intrinsics.c
index a5f5ecf..f52aaa8 100644
--- a/intel/filter_sse2_intrinsics.c
+++ b/intel/filter_sse2_intrinsics.c
@@ -1,12 +1,11 @@
 
 /* filter_sse2_intrinsics.c - SSE2 optimized filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2016-2017 Glenn Randers-Pehrson
  * Written by Mike Klein and Matt Sarett
  * Derived from arm/filter_neon_intrinsics.c
  *
- * Last changed in libpng 1.6.31 [July 27, 2017]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
diff --git a/intel/intel_init.c b/intel/intel_init.c
index 8f08baf..2f8168b 100644
--- a/intel/intel_init.c
+++ b/intel/intel_init.c
@@ -1,12 +1,11 @@
 
 /* intel_init.c - SSE2 optimized filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2016-2017 Glenn Randers-Pehrson
  * Written by Mike Klein and Matt Sarett, Google, Inc.
  * Derived from arm/arm_init.c
  *
- * Last changed in libpng 1.6.29 [March 16, 2017]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
diff --git a/mips/filter_msa_intrinsics.c b/mips/filter_msa_intrinsics.c
index 5705628..a579179 100644
--- a/mips/filter_msa_intrinsics.c
+++ b/mips/filter_msa_intrinsics.c
@@ -1,14 +1,15 @@
 
 /* filter_msa_intrinsics.c - MSA optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2016 Glenn Randers-Pehrson
  * Written by Mandar Sahastrabuddhe, August 2016.
- * Last changed in libpng 1.6.25 [September 1, 2016]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
+
 #include <stdio.h>
 #include <stdint.h>
 #include "../pngpriv.h"
diff --git a/mips/mips_init.c b/mips/mips_init.c
index 0bfb7a3..8dd283d 100644
--- a/mips/mips_init.c
+++ b/mips/mips_init.c
@@ -1,14 +1,15 @@
 
 /* mips_init.c - MSA optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2016 Glenn Randers-Pehrson
  * Written by Mandar Sahastrabuddhe, 2016.
- * Last changed in libpng 1.6.25 [September 1, 2016]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
+
 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
  * called.
  */
diff --git a/powerpc/filter_vsx_intrinsics.c b/powerpc/filter_vsx_intrinsics.c
index 93656d9..01cf880 100644
--- a/powerpc/filter_vsx_intrinsics.c
+++ b/powerpc/filter_vsx_intrinsics.c
@@ -1,13 +1,14 @@
 /* filter_vsx_intrinsics.c - PowerPC optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2017 Glenn Randers-Pehrson
  * Written by Vadim Barkov, 2017.
- * Last changed in libpng 1.6.29 [March 16, 2017]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
+
 #include <stdio.h>
 #include <stdint.h>
 #include "../pngpriv.h"
diff --git a/powerpc/powerpc_init.c b/powerpc/powerpc_init.c
index 0701617..54426c5 100644
--- a/powerpc/powerpc_init.c
+++ b/powerpc/powerpc_init.c
@@ -1,14 +1,15 @@
 
 /* powerpc_init.c - POWERPC optimised filter functions
  *
+ * Copyright (c) 2018 Cosmin Truta
  * Copyright (c) 2017 Glenn Randers-Pehrson
  * Written by Vadim Barkov, 2017.
- * Last changed in libpng 1.6.29 [March 16, 2017]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  */
+
 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
  * called.
  */