[Fluxus] adding additional modules

[gabor papp]

> Thanks to a helpful email from Matt Jadud I think this is probably the
> right choice, as we keep all the code for fluxus in one place, and it
> can share the same build system.
agreed. i think the new modules should not do anything to the main 
SConstruct file, otherwise it well get really complex after a while.

i would imagine a new module directory called addons, or something like 
that. the main SConstruct would call all SConscript files in the 
directories under addons. each module have to detect the requirements 
and compile/install or just silently fail if the library requirements 
are not met.

we could also make a packages directory with folders for the osx, 
debian, fedora, etc. specific files. what do you think?

best,
gabor