Distribute data with layers instead of data/ dir

This was originally done to make the gitignoring easier, but ended up
being somewhat more complex when trying to include files, so they're
moving out closer to the point of use.

Makefile

@@ -14,4 +14,11 @@ build: # TODO: add get_data as a prereq
 # this file much more often. Maybe as things stabilize!
 .PHONY: get_data
 get_data:
-	./data/get_all_data.sh
+	@find ./ -name "get_data.*" \! -executable | grep . >/dev/null \
+		&& echo "Non-executable files found; consider running:" \
+		&& find ./ -name "get_data.*" \! -executable -exec echo " " chmod +x {} \; \
+		&& exit 1 \
+		|| true
+
+	@find ./ -name "get_data.*" -executable \
+			-exec sh -c 'cd $$(dirname {}) && echo processing {}; ./$$(basename {}) | sed --unbuffered "s/^/    /"' \;