Output to file is now default and happens in the step() function of the Simulation class. MainBatch streamlined and simplified, initPair is for now the default initial condition for non-graphical simulations. New variables included, namely gridStep and tMax, such that the simulations started from the bash finish after tMax/timeStep iterations. In the following commit I will change the format and content of output files.
Output of particle locations and velocities into "particles_seq.txt" has been implemented. In the next commit grid observables have to be implemented in a different file.