Extended "BangEvent" to hold a "Target" and use this new information in "UpdateSchemeEventDriven" and "UpdateSchemeSequential".

VadereSimulator/src/org/vadere/simulator/control/Simulation.java:
- Extracted new method "createControllers()" which is used in constructor.

VadereState/src/org/vadere/state/attributes/scenario/AttributesAbsorbingArea.java:
- Removed unused attribute "waitingTime".
- Changed default value for attribute "deletionDistance" from "0.1" to "0.0".

New scenario element "AbsorbingArea" is not handled in:
- AbsorbingAreaController (this class is missing completely at the moment).
- MigrationAssistant (must add node '"absorbingAreas" : [ ]' to topography tree).
- DefaultConfig (to be able to change color).
- TikzGenerator (must use "topography.getAbsorbingAreas()" to iterate over the new scenario element).

Added two additional test scenarios:
- wait_event_2_sources_2_targets_osm_event_driven.scenario
- wait_event_recurring_2_sources_2_targets_osm_sequential.scenario

VadereSimulator/tests/org/vadere/simulator/control/events/EventControllerTest.java:
- Adapted unit tests for this logical change.

Added "BangEvent", process it in "CognitionLayer" and added dummy behavior in "UpdateSchemeSequential" and "UpdateSchemeEventDriven".

VadereSimulator/src/org/vadere/simulator/models/potential/combinedPotentials/CombinedPotentialStrategy.java:
- Renamed this interface to "ICombinedPotentialStrategy".
- Added enum "CombinedPotentialStrategy".

Added package "simulator/models/potential/combinedPotentials/" to encapsulate strategy pattern classes for bang event.