Rework ATWriter/Exporter - Make the write function static as both data and gauge information is necessary for writing. - Use the rivers WST unit for the gauge datum - Handle the case that we are at a gauge - Differentiate between calculated values - Always work with w in CM and thus avoid double number format problems

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