`embark reset` should cleanup dapp's node_modules/.cache

cmd/cmd_controller.js

@@ -406,6 +406,7 @@ class EmbarkController {
     var fs = require('../lib/core/fs.js');
     fs.removeSync('./chains.json');
     fs.removeSync('.embark/');
+    fs.removeSync('node_modules/.cache');
     fs.removeSync('dist/');
     console.log(__("reset done!").green);
   }