Add subtitle field to Location

Starting in Gen VI, locations have been able to have an optional
subtitle. In-game, the subtitle is displayed on a second line under the
main name.

In X/Y this is used to give some locations an alternate,
flavorful name; for example, Kalos Route 2 is also known as Avance
Trail. In S/M this is mainly used to divide some large locations like
Hau'oli City into separate sections: e.g., the Beachfront, the Shopping
District, and the Marina.

This commit just adds the column; there are no data changes.

I suppose we'll need to go back and re-rip X/Y location names now.

pokedex/db/tables.py

@@ -1112,6 +1112,11 @@ create_translation_table('location_names', Location, 'names',
     name = Column(Unicode(79), nullable=False, index=True,
         doc=u"The name",
         info=dict(format='plaintext', official=True)),
+    subtitle = Column(Unicode(79), nullable=True, index=False,
+        doc=u"""A subtitle for the location, if any.
+            This may be an alternate name for the locaton, as in the Kalos routes,
+            or the name of a subarea of the location, as in Alola.""",
+        info=dict(format='plaintext', official=True)),
 )
 
 class LocationArea(TableBase):