Update documentation for Python 3 support (issue 2550968, issue 2550980).

A few obsolete references to Python 2.3 or 2.4 also removed or
updated.

Author: jsm28

CHANGES.txt

@@ -8,7 +8,8 @@ Entries without name were done by Richard Jones.
 
 **IMPORTANT** The v1.5.x releases of Roundup were the last to support
 Python v2.5 and v2.6.  Starting with the v1.6 releases of Roundup
-v2.7.2 is required to run newer releases of Roundup.
+v2.7.2 is required to run newer releases of Roundup.  From v?.?
+onwards Python 3.4 and later are also supported.
 
 
 2018-??-?? ?.?.0
@@ -27,6 +28,9 @@ Features:
 - issue2550967: the jinja2 loader has been extended to look for .xml
   files as well as .html files similar to the TAL loader. (Christof
   Meerwald)
+- Support for Python 3 (3.4 and later).  See doc/upgrading.txt for
+  details of what is required to move an existing tracker from Python
+  2 to Python 3 (Joseph Myers, Christof Meerwald)
 
 Fixed:
 

doc/customizing.txt

@@ -2339,9 +2339,6 @@ The following variables are available to templates.
     If no translation is found, return singular if *number* is 1;
     return plural otherwise.
 
-    This function requires python2.3; in earlier python versions
-    may not work as expected.
-
 The context variable
 ~~~~~~~~~~~~~~~~~~~~
 

doc/features.txt

@@ -12,7 +12,7 @@ from Ka-Ping Yee in the Software Carpentry "Track" design competition.
  - two templates included in the distribution for you to base your tracker on
  - play with the demo, customise it and then use *it* as the template for
    your production tracker
- - requires *no* additional support software - python (2.3+ but not 3+) is
+ - requires *no* additional support software - python (2.7 or 3.4+) is
    enough to get you going
  - easy to set up higher-performance storage backends like sqlite_,
    mysql_ and postgresql_

doc/installation.txt

@@ -31,7 +31,7 @@ Roundup scripts
 Prerequisites
 =============
 
-Roundup requires Python 2.7 or newer (but not Python 3) with a functioning
+Roundup requires Python 2.7 or 3.4 or newer with a functioning
 anydbm module. Download the latest version from http://www.python.org/.
 It is highly recommended that users install the latest patch version
 of python as these contain many fixes to serious bugs.

doc/upgrading.txt

@@ -38,6 +38,20 @@ https://pypi.org/project/MySQL-python/ is still supported, it is
 recommended to switch to the updated module from
 https://pypi.org/project/mysqlclient/.
 
+Python 3 support
+----------------
+
+Many of the ``.html`` and ``.py`` files from Roundup that are copied
+into tracker directories have changed for Python 3 support.  If you
+wish to move an existing tracker to Python 3, you need to merge in
+those changes.  If your tracker uses the ``anydbm`` backend, you also
+need to export the tracker contents using ``roundup-admin export``
+running under Python 2, and them import them using ``roundup-admin
+import`` running under Python 3, as for a migration to a different
+backend.  If using the ``sqlite`` backend, you do not need to export
+and import, but need to delete the ``db/otks`` and ``db/sessions``
+files when changing Python version.
+
 Migrating from 1.5.1 to 1.6.0
 =============================
 

doc/user_guide.txt

@@ -630,7 +630,7 @@ POP:
  not supplied on the command-line.
 
 POPS:
- Connect to a POP server over ssl. This requires python 2.4 or later.
+ Connect to a POP server over ssl.
  This supports the same notation as POP::
 
     pops username:password@server

setup.py

@@ -139,7 +139,12 @@ def main():
                        'Operating System :: Microsoft :: Windows',
                        'Operating System :: POSIX',
                        'Programming Language :: Python',
-                       'Programming Language :: Python :: 2 :: Only',
+                       'Programming Language :: Python :: 2',
+                       'Programming Language :: Python :: 2.7',
+                       'Programming Language :: Python :: 3',
+                       'Programming Language :: Python :: 3.4',
+                       'Programming Language :: Python :: 3.5',
+                       'Programming Language :: Python :: 3.6',
                        'Topic :: Communications :: Email',
                        'Topic :: Office/Business',
                        'Topic :: Software Development :: Bug Tracking',