finished Grid.cs and more

Grid.cs:
-Finished everything
SimulationController.cs:
-implemented selecetCrossing(), addCrossing(), removeCrossing() and
clearGrid() :
GUI.cs:
-added displayCrossingSettings() method
-only draws crossing when starting simulation
made cars move

also fixed drawCar() to be general
small fixes

fixed move() in Car.cs
removed useless comments in calculateTurn() in Car.cs
fixed drawCar() in GUI.cs
corrected move() and UI elements alignment

also made intersection lane of crossing2 not null