Pass --no_native option to dialyzer to improve dialyzing times

Goes from 36s to 24s on my laptop.

Makefile

@@ -29,8 +29,8 @@ build-plt:
 		--apps kernel stdlib sasl inets crypto public_key ssl
 
 dialyze:
-	@$(DIALYZER) --src src --plt .cowboy_dialyzer.plt -Werror_handling \
-		-Wrace_conditions -Wunmatched_returns # -Wunderspecs
+	@$(DIALYZER) --src src --plt .cowboy_dialyzer.plt --no_native \
+		-Werror_handling -Wrace_conditions -Wunmatched_returns # -Wunderspecs
 
 docs:
 	@$(REBAR) doc skip_deps=true