Make the clean task remove the dist directory and the default task create it

Makefile

@@ -13,6 +13,6 @@ node_modules/:
 	npm install
 
 clean:
-	rm -rf ./bower_components ./node_modules
+	rm -rf ./bower_components ./node_modules ./dist
 
-.PHONY: clean lint test
+.PHONY: clean lint test make dist/fetch.umd.js dist/fetch.umd.js.flow