Add makefile - this commit is dedicated to @jbenet

Makefile

@@ -0,0 +1,19 @@
+all: deps test build
+
+deps:
+	@npm install
+
+test:
+	@npm run test
+	
+build:
+	@npm run build
+	@echo "Build success!"
+	@echo "Output: 'dist/', 'examples/browser/'"
+
+clean:
+	rm -rf orbit-db/
+	rm -rf ipfs/
+	rm -rf node_modules/
+
+.PHONY: all deps test clean