ulo: filter out what ULO features are used by the exports

ulo/ulo-used.txt

+The following is a list of ULO IRIs used as predicate in the Coq
+and Isabelle Distribution (not AFP) datasets
+
+    http://ulo.mathhub.infoderived
+    http://ulo.mathhub.infodocref
+    http://ulo.mathhub.infouses
+    http://ulo.mathhub.infointernal-size
+    http://ulo.mathhub.infosourceref
+    http://ulo.mathhub.infostatement
+    http://ulo.mathhub.infoproposition
+    http://ulo.mathhub.infodefinition
+    http://ulo.mathhub.infodeclares
+    http://ulo.mathhub.infoobject
+    http://ulo.mathhub.infotheory
+    http://ulo.mathhub.infotype
+    http://ulo.mathhub.infoaxiom
+    http://ulo.mathhub.infoprimitive
+    http://ulo.mathhub.infopredicate
+    http://ulo.mathhub.infoexample
+    http://ulo.mathhub.infolibrary
+    http://ulo.mathhub.inforevision
+    http://ulo.mathhub.infofolder
+    http://ulo.mathhub.infofile
+    http://ulo.mathhub.infolibrary-group
+    https://mathhub.info/ulotheory
+    https://mathhub.info/ulocheck-time
+    https://mathhub.info/uloexternal-size
+    https://mathhub.info/ulospecifies
+    https://mathhub.info/ulospecified-in
+    https://mathhub.info/uloname
+    https://mathhub.info/ulosection
+    https://mathhub.info/ulosourceref
+    https://mathhub.info/ulouniverse
+    https://mathhub.info/ulouses
+    https://mathhub.info/ulopredicate
+    https://mathhub.info/ulodefines
+    https://mathhub.info/ulostatement
+    https://mathhub.info/uloderived
+    https://mathhub.info/uloinstance-of
+    https://mathhub.info/ulojustifies
+    https://mathhub.info/ulotype
+    https://mathhub.info/ulofunction
+    https://mathhub.info/ulopara
+    https://mathhub.info/uloparatype
+    https://mathhub.info/uloprimitive
+    https://mathhub.info/ulodefinition
+    https://mathhub.info/uloimportant
+    https://mathhub.info/ulounimportant
+    https://mathhub.info/uloinductive-on
+    https://mathhub.info/uloexperimental