Add capped interface, python interface and test for capped, expire

Makefile

@@ -6,7 +6,7 @@ INPUTS = $(wildcard solidity/*.sol)
 OUTPUTS_JSON = $(patsubst %.sol, %.json, $(INPUTS))
 OUTPUTS_INTERFACE = $(patsubst %.sol, %.interface, $(INPUTS))
 OUTPUTS = $(OUTPUTS_JSON) $(OUTPUTS_INTERFACE)
-PREFIX = /usr/local/share/cic/solidity/abi
+PREFIX = $(DESTDIR)/usr/local/share/cic/solidity/abi
 
 #%.abi.json: $(wildcard *.sol)
 #	install -vDm0644 $@ $(PREFIX)/$@
@@ -44,4 +44,7 @@ readme:
 	make -C doc/texinfo readme
 	pandoc -f docbook -t gfm doc/texinfo/build/docbook.xml > README.md
 
+python:
+	make -C python
+
 .PHONY: clean install