Improvements

Improves SqliteTrajectoryWriter write performance at the cost of resilience.

We now batch a configurable number of iterations into one transaction without any failover support. This may lead to data-loss if the simulation gets interrupted or crashes but we consider the output not important enough to trade off speed for it. Users may want to provide their own slower but synchronized writer if they so desire.

Be aware that the buffered iterations are stored in memory so will need to tune the number of iterations based on the number of agents and your available memory.