Add extensive tests for checking valid configurations

Add extensive tests for checking valid configurations

An example event structure was given and all
possible subsets of its events were tested for
completeness. Each subset was tested for whether
it was a maximal subset of events (i.e. one for
which no element causes any of the others) and
for whether the set of events qualified for being
a configuration.

An additional observation was made concerning the determination of
whether or not a set of events is maximal. To compute
the maximal events of a given set of events, it suffices
to search the entire history of the events and eliminate
events from the original set as they appear. Note that only
events in the set itself can ever be maximal, as all other
events discovered in the search must have come from one
of these event's dependencies, or one of their dependencies'
dependencies, and so on.