Don't faucet in development

app/scripts/lib/auto-faucet.js

@@ -1,6 +1,8 @@
-var uri = 'https://faucet.metamask.io/'
+const uri = 'https://faucet.metamask.io/'
+const METAMASK_DEBUG = 'GULP_METAMASK_DEBUG'
 
 module.exports = function (address) {
+  if (METAMASK_DEBUG) return // Don't faucet in development
   var http = new XMLHttpRequest()
   var data = address
   http.open('POST', uri, true)