fixes getRandomEdge in EdgesHs

now, the random edge is retrieved by iterating over all elements
instead of transforming the set to an array and drawing a random element
update filesystem keywords
changes plot prefixes
adds util methods to ArrayUtils
adds flag to turn on garbage collection after each batch
adds undirected graph generators: clique and ring
adds implementations of the shortest paths metric (APSP)
adds undirected network generator (growing network)
adds application of all updates to Batch.apply(…)
updates constructors for TimelineBatch generators to allow arbitrary number of parameters