Add test and clean targets to Makefile.

Makefile

-.PHONY: install
+.PHONY: install clean test
 
 install:
 	cp ssl-ca /usr/local/bin/ssl-ca
 	chmod 755 /usr/local/bin/ssl-ca
+
+clean:
+	rm -rf openssl.cnf certs keys CA.key CA.crt
+
+test: clean
+	./ssl-ca init
+	./ssl-ca gen www
+	openssl genrsa -out keys/smtp
+	./ssl-ca sign
+	./ssl-ca resign