  plschr(def, scale)
  ******************

  plschr

  This sets up the size of all subsequent characters drawn. The actual
  height of a character is the product of the default character size and a
  scaling factor.

  def (PLFLT, input): The default height of a character in millimeters,
  should be set to zero if the default height is to remain unchanged.

  scale (PLFLT, input): Scale factor to be applied to default to get
  actual character height.

