[Fluxus] new fluxus module demo

[gabor papp]

> It's easier in some ways if they all go into fluxus git - but in order
> to prevent a big increase in dependencies we should have checking in the
> SConstruct - i.e. only build the OpenAL module if it's installed, only
> build the AR module if ar-toolkit is present etc etc. 
i agree. i was thinking to have a directory like 'addons', in which all 
modules compile independently from fluxus. they would have their own 
scons file.

best,
gabor