Renommer `normalvalue.computedvalue` en `normalvalue.median`. refs www#60

sql/schema.functions.sql

@@ -14,7 +14,7 @@ i.id AS "indicator",
 s.cell,
 s.enddate AS date,
 s.rawvalue AS computedvalue,
-COALESCE(s.rawvalue - n."median", 0) AS comparedvalue
+COALESCE(s.rawvalue - n."medianvalue", 0) AS comparedvalue
 FROM %1$s AS s
 	JOIN agrometinfo."indicator" AS i ON i.code=s."indicator"
 	JOIN agrometinfo."period" AS p ON p.id=i."period" AND p.phase=s.phase