Widespread usage of Location::location_t

* Makefile
Added new file to sources (src/CrowdSimulation.cpp).

* include/sim_crowd/types.hpp
New location types and values.

* include/AreaCell.hpp
* include/EventArea.hpp
* src/EventArea.cpp
* src/Unit.cpp
Deleted old location constants in EventArea, now there is
Location::location_t type in usage. This change implies other changes.

* src/main.cpp
Some small cleanup.