Makefile, test: add installation and uninstallation of menu(1)

Makefile

@@ -1,3 +1,7 @@
+PREFIX ?= /usr/local
+DESTDIR ?=
+BINDIR ?= $(PREFIX)/bin
+
 menu: menu.rs
 	rustc -o $@ $@.rs
 
@@ -11,3 +15,8 @@ test: menu
 
 .PHONY: install
 install: menu
+	install -m 755 menu $(PREFIX)/bin
+
+.PHONY: uninstall
+uninstall:
+	rm -f $(PREFIX)/bin/menu

test

@@ -12,10 +12,22 @@ Remove menu and re-build it.
 
 	rm -f menu; make
 
-Install to /usr/local/ (assuming adequate permissions).
+Install menu to /usr/local/ (assuming adequate permissions).
 
-	make install
+	make PREFIX=/usr/local/ install
 
-Install to /usr/local/ (using sudo(8)).
+Install menu to /usr/local/ (using sudo(8)).
 
-	sudo make install
+	sudo make PREFIX=/usr/local install
+
+Uninstall menu from /usr/local (assuming adequate permissions).
+
+	make PREFIX=/usr/local/ uninstall
+
+Uninstall menu from /usr/local (using sudo(8)).
+
+	sudo make PREFIX=/usr/local/ uninstall
+
+Open the ytfeed launcher.
+
+	make -C examples -f Makefile.ytfeed