update file headers with license information (SPDX)
diff --git a/serial/tools/list_ports.py b/serial/tools/list_ports.py
index 403b405..468411a 100644
--- a/serial/tools/list_ports.py
+++ b/serial/tools/list_ports.py
@@ -5,7 +5,8 @@
 # port enumeration feature
 #
 # (C) 2011-2015 Chris Liechti <cliechti@gmx.net>
-# this is distributed under a free software license, see license.txt
+#
+# SPDX-License-Identifier:    BSD-3-Clause
 
 """\
 This module will provide a function called comports that returns an
diff --git a/serial/tools/list_ports_linux.py b/serial/tools/list_ports_linux.py
index 8ca1565..11092b5 100644
--- a/serial/tools/list_ports_linux.py
+++ b/serial/tools/list_ports_linux.py
@@ -1,12 +1,13 @@
 #!/usr/bin/env python

-

+#

 # portable serial port access with python

 #

 # This is a module that gathers a list of serial ports including details on

 # GNU/Linux systems

 #

-# (C) 2011-2013 Chris Liechti <cliechti@gmx.net>

-# this is distributed under a free software license, see license.txt

+# (C) 2011-2015 Chris Liechti <cliechti@gmx.net>

+#

+# SPDX-License-Identifier:    BSD-3-Clause

 

 import glob

 import sys

diff --git a/serial/tools/list_ports_osx.py b/serial/tools/list_ports_osx.py
index fbce6f2..a451ae6 100644
--- a/serial/tools/list_ports_osx.py
+++ b/serial/tools/list_ports_osx.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-
+#
 # portable serial port access with python
 #
 # This is a module that gathers a list of serial ports including details on OSX
@@ -8,7 +8,9 @@
 # with contributions from cibomahto, dgs3, FarMcKon, tedbrandston
 # and modifications by cliechti
 #
-# this is distributed under a free software license, see license.txt
+# (C) 2013-2015
+#
+# SPDX-License-Identifier:    BSD-3-Clause
 
 
 
diff --git a/serial/tools/list_ports_posix.py b/serial/tools/list_ports_posix.py
index d90d6af..a1a3faf 100644
--- a/serial/tools/list_ports_posix.py
+++ b/serial/tools/list_ports_posix.py
@@ -8,8 +8,9 @@
 # this is a wrapper module for different platform implementations of the

 # port enumeration feature

 #

-# (C) 2011-2013 Chris Liechti <cliechti@gmx.net>

-# this is distributed under a free software license, see license.txt

+# (C) 2011-2015 Chris Liechti <cliechti@gmx.net>

+#

+# SPDX-License-Identifier:    BSD-3-Clause

 

 """\

 The ``comports`` function is expected to return an iterable that yields tuples

@@ -102,3 +103,4 @@
 if __name__ == '__main__':

     for port, desc, hwid in sorted(comports()):

         print("%s: %s [%s]" % (port, desc, hwid))

+

diff --git a/serial/tools/list_ports_windows.py b/serial/tools/list_ports_windows.py
index 4d52d3f..c285dde 100644
--- a/serial/tools/list_ports_windows.py
+++ b/serial/tools/list_ports_windows.py
@@ -1,3 +1,12 @@
+#! python

+#

+# Enumerate serial ports on Windows including a human readable description

+# and hardware information.

+#

+# (C) 2001-2015 Chris Liechti <cliechti@gmx.net>

+#

+# SPDX-License-Identifier:    BSD-3-Clause

+

 import ctypes

 import re

 

@@ -239,3 +248,4 @@
 

     for port, desc, hwid in sorted(comports()):

         print("%s: %s [%s]" % (port, desc, hwid))

+

diff --git a/serial/tools/miniterm.py b/serial/tools/miniterm.py
index 85cc75a..2bee68b 100644
--- a/serial/tools/miniterm.py
+++ b/serial/tools/miniterm.py
@@ -1,6 +1,10 @@
 #!/usr/bin/env python
+#
 # Very simple serial terminal
+#
 # (C)2002-2015 Chris Liechti <cliechti@gmx.net>
+#
+# SPDX-License-Identifier:    BSD-3-Clause
 
 # Input characters are sent directly (only LF -> CR/LF/CRLF translation is
 # done), received characters are displayed as is (or escaped through pythons