Fix make help’s unclosed strings

Makefile

@@ -47,8 +47,8 @@ help:
 	@echo " pot           Generate a gettext POT file to be used for translations."
 	@echo " release       Prepare a new release of converse.js. E.g. make release VERSION=0.9.5"
 	@echo " serve         Serve this directory via a webserver on port 8000."
-	@echo " stamp-npm  	  Install NPM dependencies
-	@echo " stamp-bundler Install Bundler (Ruby) dependencies
+	@echo " stamp-npm     Install NPM dependencies"
+	@echo " stamp-bundler Install Bundler (Ruby) dependencies"
 	@echo " watch         Tells Sass to watch the .scss files for changes and then automatically update the CSS files."