Add lua scripting to fluxbox

by pavelo for fluxbox

In order to enhance the configurability of fluxbox, we propose to add lua scripting. Full blown scripting language will not limit the power users and the intuitive syntax of lua should not be a burden on the casual user. Backward compatibility will be provided by special converters from the old configuration files. A side effect of this project will be the unification of syntax of various configuration files fluxbox has acquired over the years.