Add Makefile for multishell testing

updated nvm current test for zsh

Makefile

@@ -0,0 +1,15 @@
+URCHIN=`which urchin`
+SHELLS=sh bash dash ksh zsh
+
+.PHONY: $(SHELLS) test
+
+fast: $(SHELLS)
+
+$(SHELLS):
+	@printf '\n\033[0;34m%s\033[0m\n' "Running tests in $@"
+	@$@ $(URCHIN) -f test/fast
+
+test: fast
+	@$(URCHIN) -f test/slow 
+
+default: test