contains the framework: the setup, setting up each
module, and the Event loop.
holds the Module base class. This likely already is
part of the experiment framework, or it may be added
to define modules for error logging purposes.
contains the definition of Event, whiich is very
simple here but would be huge in reality. .cc only.
contains the physics code written by group A to act
as module A.
contains the physics code written by group B to act
as module B.