by_json: Generate circulation policies

* Generate a new circulation policies file: policies.svg
  * Parses Circulation policies
  * Parses Item Types

by_json/Makefile

@@ -1,4 +1,4 @@
-all: orgas.svg
+all: orgas.svg policies.svg
 
 # All .dot files are generated by gen_%.sh file (gen_orgas.sh for example)
 %.dot: gen_%.sh
@@ -9,3 +9,6 @@ all: orgas.svg
 
 clean:
 	rm -f *.svg *.dot
+
+# Keep temporary files (dot files) for debug
+.PRECIOUS: %.dot