Export fromKey converter as well from GEODE

lib/python/GEODE/__init__.py

 from GEODE.Classification import discursiveFunctions
-from GEODE.Metadata import article, paragraph, relativePath, toKey, uid
+from GEODE.Metadata import article, paragraph, fromKey, relativePath, toKey, uid
 from GEODE.store import corpus, Directory, SelfContained, toTSV
 from GEODE.Visualisation import heatmap