Add udhr dataset to cli and top level of dataset subpkg

Author: bdewilde

textacy/__main__.py

@@ -27,6 +27,7 @@
     "oxford_text_archive": datasets.OxfordTextArchive,
     "reddit_comments": datasets.RedditComments,
     "supreme_court": datasets.SupremeCourt,
+    "udhr": datasets.UDHR,
     "wikinews": datasets.Wikinews,
     "wikipedia": datasets.Wikipedia,
     "concept_net": resources.ConceptNet,

textacy/datasets/__init__.py

@@ -4,3 +4,4 @@
 from .reddit_comments import RedditComments
 from .supreme_court import SupremeCourt
 from .wikimedia import Wikipedia, Wikinews
+from .udhr import UDHR