Routine Name:	position

Description:	Sets xyz coordinates of an element and all of its children.

Usage:		position element x y z

		element		element whose coordinates to specify

		x, y, z		x, y, z coordinates to give element; to
				specify absolute coordinates, use a number;
				to specify coordinates relative to the current
				position, use the form Rnumber; to ignore the
				coordinate (leave it as it is), use I

Example:	position /neuron 10 20 4.6
		position /neuron I I R5.2
		position /neuron 1.5 R1.1 I
		position /V1/horiz 0 0 {-5 * V1_SEPZ}

Notes:		This routine affects the positions of the child elements as
		well as that of the parent.

