add deprecation warning for web3

app/scripts/lib/auto-reload.js

@@ -5,7 +5,10 @@ function setupDappAutoReload (web3, observable) {
   global.web3 = new Proxy(web3, {
     get: (_web3, name) => {
       // get the time of use
-      if (name !== '_used') _web3._used = Date.now()
+      if (name !== '_used') {
+        console.warn('MetaMask: web3 will be deprecated in the future in favor of the ethereumProvider \nhttps://github.com/ethereum/mist/releases/tag/v0.9.0')
+        _web3._used = Date.now()
+      }
       return _web3[name]
     },
     set: (_web3, name, value) => {