define a plugin interface

[aoloe]

• http://qt-project.org/doc/qt-4.8/plugins-howto.html (cf. the lower-level API)
• http://qt-project.org/doc/qt-5.1/qtcore/qpluginloader.html (cf. description)
• http://qt-project.org/doc/qt-4.8/tools-plugandpaint.html (a sample draw app with plugins; cf. mainwindow)
  with a plugin http://qt-project.org/doc/qt-4.8/tools-plugandpaintplugins-basictools.html (but one which is installed as a higher-lever API)
• http://www.siteduzero.com/informatique/tutoriels/qt-creation-de-plugins (a step by step howto)
• for getting the "default" plugins to be compiled when the main project is compiled, have a look at the .pro and .pri files in qt creator (http://qt.gitorious.org/qt-creator/qt-creator)
• and here is a plugin loader implemented as a template: http://www.siteduzero.com/informatique/tutoriels/qt-creation-de-plugins/le-chargeur-de-plugin
• some general notes on how to correctly create and manage plugins in c++: http://blog.nuclex-games.com/tutorials/cxx/plugin-architecture/

in Qt4, plugins have to be loaded in order to read information. as of version 5, it is now possible to retrieve information from a plugin without even loading it (http://dtk.inria.fr/blog/?p=502).

[aoloe]

a basic plugin loader is there and a first (empty) plugin also. yeah.