Potentials for cellular automaton - no repulsion from walls / other pedestrians - only high values at other pedestrian's positions and at obstacles.

Implemented new functionality on client side. Working on implementing setVelocity, but currently, EOFException is thrown.

remove hard coded path from test client. add short api name to easy use of cmdClient

See merge request !87

If the getTargetId TraCI-Command is executed with the targetId "-1" (invalid for any agent) then the command returns a list of all targetIds currently in the simulation.

# Conflicts:
#   VadereManager/src/org/vadere/manager/client/TestClient.java

If the getTargetId TraCI-Command is executed with the targetId "-1" (invalid for any agent) then the command returns a list of all targetIds currently in the simulation.

In "run_vadere_console_with_all_scenario_files.py", use "os.path.join()" instead of hard-coded platform-specific path separator

In ".gitlab-ci.yml", deleted outdated comments and made stages "unit_test" and "integration_test" more robust

VadereGui/src/org/vadere/gui/onlinevisualization/view/OnlineVisualisationWindow.java:
- Fixed bug: The scroll pane was not added to the underlying model.
  Therefore, it was not possible to capture mouse wheel events.