Add note about limiting auto scale range

Thanks to Sabine Tobolka for discovering this. See
https://groups.google.com/d/msg/pywws/2vsHjjlrr8Q/kAoMMjb-AAAJ

Signed-off-by: Jim Easterbrook <jim@jim-easterbrook.me.uk>

src/pywws/Plot.py

@@ -3,7 +3,7 @@
 
 # pywws - Python software for USB Wireless Weather Stations
 # http://github.com/jim-easterbrook/pywws
-# Copyright (C) 2008-15  pywws contributors
+# Copyright (C) 2008-16  pywws contributors
 
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -311,6 +311,12 @@
 example, to have the upper value auto scale whilst fixing the lower
 value at zero, use ``<yrange>0:*</yrange>``.
 
+Since gnuplot version 4.6 you can set lower and/or upper bounds of the
+auto scaled range. The gnuplot syntax for this is ``lo < * < hi``, but
+as the plot template is an XML file we need to replace the ``<``
+characters with ``&lt;``. For example, if we want the upper value to
+always be 20 or more we can use ``<yrange>0:20 &lt; *</yrange>``.
+
 y2range
 ^^^^^^^
 

src/pywws/__init__.py

@@ -1,3 +1,3 @@
-__version__ = '16.04.0'
-_release = '1351'
-_commit = '8b68e6f'
+__version__ = '16.05.0'
+_release = '1352'
+_commit = '73d751e'