Stairway grid types

Variables
const int	Renga::GridTypes::Stairway::Undefined = 0
	Undefined.
const int	Renga::GridTypes::Stairway::Top = 1
	Top faces of a stairway.
const int	Renga::GridTypes::Stairway::Bottom = 2
	Bottom faces of a stairway.
const int	Renga::GridTypes::Stairway::LeftSide = 3
	Left side faces of a stairway (when looking at the starting point towards the end point)
const int	Renga::GridTypes::Stairway::RightSide = 4
	Right side face of a stairway (when looking at the starting point towards the end point)
const int	Renga::GridTypes::Stairway::Cut = 5
	Faces appearing as a result of cutting a stairway by other objects.

Possible grid types for a Stairway mesh