Routine Name:	deletefield

Description:	Deletes an extended field which has been added to an element.

Usage:		deletefield [element] field-name

Example:	genesis > addfield /soma area
		OK
		genesis > deletefield /soma area
		OK
		genesis > deletefield /soma inject
		deletefield: Cannot delete permanent field 'inject' on element '/soma'

Notes:		Only added extended field may be deleted with deletefield.

See also:	addfield

