getDirections = function(o){
					return {
							"edgeRole":o.edgeRole||undefined,
							"t": o["t"]||1,
							"r": o["r"]||1,
							"b": o["b"]||1,
							"l": o["l"]||1
						}
				}
Call this method to initialize the rules for a stencil set and all of its
active extensions.

@param {Object}
           stencilSet