Remove special handling for Python < 2.6

See #701.

Doc/Manual/Python.html

@@ -150,9 +150,9 @@
 
 <p>
 This chapter describes SWIG's support of Python.  SWIG is compatible
-with most recent Python versions including Python 3.0 and Python 2.6,
-as well as older versions dating back to Python 2.0.  For the best results,
-consider using Python 2.3 or newer.
+with most recent Python versions (Python 2.6 and later, including Python 3).
+If you still need to generate bindings which work with older versions of
+Python, you'll have to use SWIG 3.0.x.
 </p>
 
 <p>
@@ -860,8 +860,8 @@ installation under "Additional include directories".
 
 <li>Finally, select the settings for the entire project and go to
 "Link Options".  Add the Python library file to your link libraries.
-For example "python21.lib".  Also, set the name of the output file to
-match the name of your Python module, ie. _example.pyd - Note that _example.dll also worked with Python-2.4 and earlier.
+For example "python27.lib".  Also, set the name of the output file to
+match the name of your Python module, i.e. <tt>_example.pyd</tt>
 
 <li>Build your project.
 </ul>
@@ -2290,13 +2290,6 @@ please refer to the python documentation:</p>
 
 <p>Use of the <tt>-builtin</tt> option implies a couple of limitations:
 <ul>
-  <li><p>python version support:</p>
-  <ul>
-    <li>Versions 2.5 and up are fully supported</li>
-    <li>Versions 2.3 and 2.4 are mostly supported; there are problems with director classes and/or sub-classing a wrapped type in python.</li>
-    <li>Versions older than 2.3 are not supported.</li>
-  </ul>
-  </li>
   <li><p>Some legacy syntax is no longer supported; in particular:</p>
   <ul>
     <li>The functional interface is no longer exposed.  For example, you may no longer call <tt>Whizzo.new_CrunchyFrog()</tt>.  Instead, you must use <tt>Whizzo.CrunchyFrog()</tt>.</li>
@@ -2808,43 +2801,6 @@ It is also possible to deal with situations like this using
 typemaps--an advanced topic discussed later.
 </p>
 
-<H3><a name="Python_nn31">38.4.4 Python 2.2 and classic classes</a></H3>
-
-
-<p>
-SWIG makes every attempt to preserve backwards compatibility with
-older versions of Python to the extent that it is possible.  However,
-in Python-2.2, an entirely new type of class system was introduced.
-This new-style class system offers many enhancements including static
-member functions, properties (managed attributes), and class methods.
-Details about all of these changes can be found on <a
-href="https://www.python.org">www.python.org</a> and is not repeated here.
-</p>
-
-<p>
-To address differences between Python versions, SWIG currently emits
-dual-mode proxy class wrappers.  In Python-2.2 and newer releases,
-these wrappers encapsulate C++ objects in new-style classes that take
-advantage of new features (static methods and properties).  However,
-if these very same wrappers are imported into an older version of Python,
-old-style classes are used instead.
-</p>
-
-<p>
-This dual-nature of the wrapper code means that you can create extension
-modules with SWIG and those modules will work with all versions of Python
-ranging from Python-2.0 to the very latest release.  Moreover, the wrappers take
-advantage of Python-2.2 features when available.
-</p>
-
-<p>
-For the most part, the interface presented to users is the same regardless
-of what version of Python is used.  The only incompatibility lies in the handling
-of static member functions.  In Python-2.2, they can be accessed via the
-class itself.  In Python-2.1 and earlier, they have to be accessed as a global
-function or through an instance (see the earlier section).
-</p>
-
 <H2><a name="Python_directors">38.5 Cross language polymorphism</a></H2>
 
 
@@ -3430,7 +3386,9 @@ statements.
 </p>
 
 <p>
-The following shows example usage for Python 2.6 to use <tt>print</tt> as it can in Python 3, that is, as a function instead of a statement:
+The following example for Python 2.x shows how to insert code into the
+generated wrapper to enable <tt>print</tt> to be used as a Python3-compatible
+function instead of a statement:
 </p>
 
 <div class="code">
@@ -3447,13 +3405,13 @@ print("Loading", "Whizz", "Bang", sep=' ... ')
 </div>
 
 <p>
-which can be seen when viewing the first few lines of the generated <tt>.py</tt> file:
+The insert code can be seen at the start of the generated <tt>.py</tt> file:
 </p>
 
 <div class="code">
 <pre>
 # This file was automatically generated by SWIG (http://www.swig.org).
-# Version 2.0.11
+# Version 4.0.0
 #
 # Do not make changes to this file unless you know what you are doing--modify
 # the SWIG interface file instead.
@@ -6255,8 +6213,8 @@ to do this (remember you are now the Python importer) or use dynamic linking.
 
 
 <p>
-SWIG is able to support Python 3.0. The wrapper code generated by
-SWIG can be compiled with both Python 2.x or 3.0. Further more, by
+SWIG is able to support Python 3.x. The wrapper code generated by
+SWIG can be compiled with both Python 2.x or 3.x. Further more, by
 passing the <tt>-py3</tt> command line option to SWIG, wrapper code
 with some Python 3 specific features can be generated (see below
 subsections for details of these features). The <tt>-py3</tt> option also
@@ -6274,7 +6232,7 @@ There is a list of known-to-be-broken features in Python 3:
 </ul>
 
 <p>
-The following are Python 3.0 new features that are currently supported by
+The following are Python 3 new features that are currently supported by
 SWIG.
 </p>
 
@@ -6333,8 +6291,8 @@ void get_path(char *s);
 
 <p>
 Then you can write a typemap like this: (the following example is
-applied to both Python 3.0 and 2.6, since the <tt>bytearray</tt> type
-is backported to 2.6.
+applied to both Python 2 and 3, since the <tt>bytearray</tt> type
+was backported to 2.6.
 </p>