Added a top level Makefile to build all.

Makefile

@@ -0,0 +1,12 @@
+SUBDIRS = roverif rover
+
+all: $(SUBDIRS:%=build-%)
+
+clean: $(SUBDIRS:%=clean-%)
+
+build-%:
+	$(MAKE) -C $*
+
+clean-%:
+	$(MAKE) -C $* clean
+