Fix area label rendering. Previously the showarealabel setting was neither parsed nor used to decide if the arealabel should be drawn. It is mostly off but enabled for Cross Sections. It is now also shown in the style editors in case someone got used to it ;)

SYMBOLSET
SYMBOL
  NAME 'point'
  TYPE ELLIPSE
  POINTS
    1 1
  END
  FILLED TRUE
END
SYMBOL
  NAME "square"
  TYPE VECTOR
  POINTS
    0 0
    0 1
    1 1
    1 0
    0 0
  END
  FILLED TRUE
END
END