remove unused function maybe (prefer Maybe.withDefault)

and also a couple of libs we weren't using

elm.json

@@ -17,9 +17,7 @@
             "elm/url": "1.0.0",
             "elm-community/list-extra": "8.7.0",
             "elm-explorations/test": "2.2.0",
-            "mpizenberg/elm-pointer-events": "5.0.0",
-            "rtfeldman/elm-iso8601-date-strings": "1.1.4",
-            "ymtszw/elm-xml-decode": "3.2.2"
+            "mpizenberg/elm-pointer-events": "5.0.0"
         },
         "indirect": {
             "elm/bytes": "1.0.8",

frontend/src/Lib.elm

@@ -4,11 +4,6 @@
 module Lib exposing(looseLabels)
 
 
-maybe default val =
-    case val of
-        Just v -> v
-        Nothing -> default
-
 -- https://github.com/cenfun/nice-ticks/blob/master/docs/Nice-Numbers-for-Graph-Labels.pdf
 
 log10 x = logBase 10 x