Python SIP bindings & Plugin Manager

Hi,

As you may have noticed there is now a trunk/sip/ directory with sip
python bindings to some of the classes. It is already possible to use
libavogadro from python but some helper classes are probably needed to
make it easier. Currently I’m working on a PluginManager class to help
loading the plugins (in libavogadro, there was no function to load
extensions). This central class will replace the functionality of
ToolGroup::load(), GLWidget::loadEngines() and
MainWindow::loadExtension(). I also added a dialog which enables the
user to enable/disable plugins.

screenshot: http://home.scarlet.be/timvdm/puginmanager.png

cheers,
Tim