Prior to this patch opening parenthesis were not considered part of the
current word, so a completion token such as ``myfunc(`` would never test
positive for a trailing ``(``.

This patch fixes completion of parameters required by a class when
creating a new instance. For example completing ``MyClass(`` should take
the parameters from ``MyClass.__init__``.

The ``_ctor`` closure within ``Completer.get_arguments`` always raised a
NameError exception because the function signature named its incoming argument
``obj`` rather than ``class_ob``.

The test that determined if ``func_obj`` is a class did not cope with
meta-classes (which are both a class, and a type). Generally ``type()``
is not a robust way to reason about the Python objects, so this patch
replaces all checks of the form::

    type(foo) == types.FooType

with calls to the ``inspect`` module, for instance::

    inspect.isclass(foo)
    inspect.ismethod(foo)
    inspect.isfuction(foo)

Completed parameters are space and comma seperated, instead of just
being comma seperated. Old behaviour::

    myfunc(a,b,c)

New behaviour::

    myfunc(a, b, c)

This better matches common practice, and the exampels in PEP 8 [1]_. If
this upsets established users, a configuration variable could be created
to control it.

.. [1] http://www.python.org/dev/peps/pep-0008/

This patch renames ``pythoncomplete.py`` to ``python_complete.py`` since
the latter is automatically loaded by Vim (tested with v7.3).

Using Vim's tracing feature (e.g. ``vim -Vtrace.log somefile.py``) I
discovered that Vim does not automatically load
``$HOME/.vim/ftplugin/pythoncomplete.vim`` without additional
configuration, it only considers the following::

    Searching for

        ftplugin/python.vim
        ftplugin/python_*.vim
        ftplugin/python/*.vim

    in

        $HOME/.vim
        /var/lib/vim/addons
        /usr/share/vim/vimfiles
        /usr/share/vim/vim73
        /usr/share/vim/vimfiles/after
        /var/lib/vim/addons/after
        $HOME/.vim/after

Note that the default distribution of Vim v7.3 [1]_ includes
`ftplugin/python.vim` which contains the following line::

    setlocal omnifunc=pythoncomplete#Complete

This conflicts with the changed introduced in this patch, and is no longer
needed (since this script now sets 'omnifunc' itself).

.. [1] At least, it does on Ubuntu v11.10's "vim-runtime" package, version
       "2:7.3.154+hg~74503f6ee649-2ubuntu3"

Until the stock `ftplugin/python.vim` drops its definition for
'omnifunc' `python_complete.vim` must be loaded after system defaults to
ensure it is actually used.

Should this version of `python_complete.vim` become the new stock
version, users should install future updates into `$HOME/.vim/ftplugin`,
since a guard at the top of the script will preventing existing
definitions being replaced.