Optimisation of algorithms and improvement of logging

• Optimisation of different algorithms with a significant reduction in running times
• Parallelisation of ExposureUpdater.update_exposure_occupants()
• Improvement of logging in general and incorporation of a detailed debug-level logging
• New parameters in the configuration file:
  • debug_logging: True/False to activate/deactivate debug-level logging
  • number_cores: Number of cores to be used in parallelised tasks