SpatialGrid: we need ceil to calculate to correct voxel numbers.
SpatialGrid: insert object instead of shape (Visitor classes ask PhysicalObjects not Shapes).
PhysicalEnvironment: missed if objectCache != "".
SpatialGrid: an obstacle may be in several voxels but we should visit it only once.
Polygon: we don't calculate the intersection if the line segment is not in the polygon's plane.
PhysicalEnvironment: parse objects in INITSTAGE_PHYSICAL_ENVIRONMENT: objectCache may not exist in LOCAL stage.
ObstacleTest: changed Polygon intersection test.
SpatialGrid: deleted an unused variable.
SpatialGrid: halve each side in boundingBoxSize (we calculate it from the center point).
ObstacleTest: OutdoorWithGridObjectCache extends Outdoor test with GridObjectCache.