Recursively collapses the tree. Given a list of nodes and a node index, each node is translated in such a way that the tree takes minimal vertical space. This is achieved by checking if the space above a node is filled (in which case the node is already drawn in an appropriate position) or not (in which case the node needs to be translated "upwards") and taking respective action.

public void CollapseTree(
	List<Node> nodes,
	int collapseIndex
)

public void CollapseTree(
	List<Node> nodes,
	int collapseIndex
)